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Author | SHA1 | Date |
---|---|---|
大耳刮子 | eb572bfaf3 | 2 years ago |
大耳刮子 | 094188df48 | 2 years ago |
pvqf6mep3 | ca6c0289ea | 2 years ago |
pvqf6mep3 | 3ce5f68bdc | 2 years ago |
Thinner123 | e15e21206e | 2 years ago |
pvqf6mep3 | bcc8ea078d | 2 years ago |
pvqf6mep3 | 6370eaabf9 | 2 years ago |
pvqf6mep3 | 470e05f375 | 2 years ago |
pvqf6mep3 | db4c8f7a7c | 2 years ago |
pvqf6mep3 | e796e5405b | 2 years ago |
pvqf6mep3 | e27a25a43b | 2 years ago |
pvqf6mep3 | b6e6b884ca | 2 years ago |
pvqf6mep3 | 37e6653753 | 2 years ago |
Thinner123 | 1c1221f89d | 2 years ago |
pvqf6mep3 | 182b92fb7d | 2 years ago |
pvqf6mep3 | e9904b96bb | 2 years ago |
hackii | 0e7846f5e8 | 2 years ago |
pvqf6mep3 | 16f7cec4dd | 2 years ago |
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@ -0,0 +1,6 @@
|
||||
projectKey=CEC
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||||
serverUrl=http://localhost:9000
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serverVersion=9.4.0.54424
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dashboardUrl=http://localhost:9000/dashboard?id=CEC
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||||
ceTaskId=AYHgkSABciXJR8mKLIhs
|
||||
ceTaskUrl=http://localhost:9000/api/ce/task?id=AYHgkSABciXJR8mKLIhs
|
@ -0,0 +1,803 @@
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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||||
// STL A* Search implementation
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||||
// (C)2001 Justin Heyes-Jones
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//
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// This uses my A* code to solve the 8-puzzle
|
||||
|
||||
////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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||||
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||||
#include <iostream>
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#include <stdio.h>
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#include <assert.h>
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#include <new>
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#include <ctype.h>
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using namespace std;
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// Configuration
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#define NUM_TIMES_TO_RUN_SEARCH 1
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#define DISPLAY_SOLUTION_FORWARDS 1
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#define DISPLAY_SOLUTION_BACKWARDS 0
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#define DISPLAY_SOLUTION_INFO 1
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#define DEBUG_LISTS 0
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// AStar search class
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#include "stlastar.h" // See header for copyright and usage information
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// Global data
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#define BOARD_WIDTH (3)
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#define BOARD_HEIGHT (3)
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#define GM_TILE (-1)
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#define GM_SPACE (0)
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#define GM_OFF_BOARD (1)
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// Definitions
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// To use the search class you must define the following calls...
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// Data
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// Your own state space information
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// Functions
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// (Optional) Constructor.
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// Nodes are created by the user, so whether you use a
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// constructor with parameters as below, or just set the object up after the
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// constructor, is up to you.
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//
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// (Optional) Destructor.
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// The destructor will be called if you create one. You
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// can rely on the default constructor unless you dynamically allocate something in
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// your data
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//
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// float GoalDistanceEstimate( PuzzleState &nodeGoal );
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// Return the estimated cost to goal from this node (pass reference to goal node)
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//
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// bool IsGoal( PuzzleState &nodeGoal );
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// Return true if this node is the goal.
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//
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// bool GetSuccessors( AStarSearch<PuzzleState> *astarsearch );
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// For each successor to this state call the AStarSearch's AddSuccessor call to
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// add each one to the current search - return false if you are out of memory and the search
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// will fail
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//
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// float GetCost( PuzzleState *successor );
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// Return the cost moving from this state to the state of successor
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//
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// bool IsSameState( PuzzleState &rhs );
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// Return true if the provided state is the same as this state
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// Here the example is the 8-puzzle state ...
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class PuzzleState
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{
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public:
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// defs
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typedef enum
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{
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TL_SPACE,
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TL_1,
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TL_2,
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TL_3,
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TL_4,
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TL_5,
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TL_6,
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TL_7,
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TL_8
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} TILE;
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// data
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static TILE g_goal[ BOARD_WIDTH*BOARD_HEIGHT];
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static TILE g_start[ BOARD_WIDTH*BOARD_HEIGHT];
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// the tile data for the 8-puzzle
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TILE tiles[ BOARD_WIDTH*BOARD_HEIGHT ];
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// member functions
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PuzzleState() {
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memcpy( tiles, g_goal, sizeof( TILE ) * BOARD_WIDTH * BOARD_HEIGHT );
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}
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PuzzleState( TILE *param_tiles )
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||||
{
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memcpy( tiles, param_tiles, sizeof( TILE ) * BOARD_WIDTH * BOARD_HEIGHT );
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||||
}
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float GoalDistanceEstimate( PuzzleState &nodeGoal );
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||||
bool IsGoal( PuzzleState &nodeGoal );
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bool GetSuccessors( AStarSearch<PuzzleState> *astarsearch, PuzzleState *parent_node );
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float GetCost( PuzzleState &successor );
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bool IsSameState( PuzzleState &rhs );
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void PrintNodeInfo();
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private:
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// User stuff - Just add what you need to help you write the above functions...
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void GetSpacePosition( PuzzleState *pn, int *rx, int *ry );
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bool LegalMove( TILE *StartTiles, TILE *TargetTiles, int spx, int spy, int tx, int ty );
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int GetMap( int x, int y, TILE *tiles );
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||||
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||||
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||||
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||||
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};
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// Goal state
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PuzzleState::TILE PuzzleState::g_goal[] =
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{
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TL_1,
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TL_2,
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TL_3,
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TL_8,
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TL_SPACE,
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TL_4,
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TL_7,
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TL_6,
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TL_5,
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};
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||||
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// Some nice Start states
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||||
PuzzleState::TILE PuzzleState::g_start[] =
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{
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||||
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||||
// Three example start states from Bratko's Prolog Programming for Artificial Intelligence
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||||
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||||
#if 1
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||||
// ex a - 4 steps
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TL_1 ,
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TL_3 ,
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TL_4 ,
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TL_8 ,
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TL_SPACE ,
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||||
TL_2 ,
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||||
TL_7 ,
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||||
TL_6 ,
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||||
TL_5 ,
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||||
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||||
#elif 0
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||||
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||||
// ex b - 5 steps
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||||
TL_2 ,
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||||
TL_8 ,
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||||
TL_3 ,
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||||
TL_1 ,
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||||
TL_6 ,
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||||
TL_4 ,
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||||
TL_7 ,
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||||
TL_SPACE ,
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||||
TL_5 ,
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||||
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||||
#elif 0
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||||
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||||
// ex c - 18 steps
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TL_2 ,
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||||
TL_1 ,
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TL_6 ,
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||||
TL_4 ,
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||||
TL_SPACE ,
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||||
TL_8 ,
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||||
TL_7 ,
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||||
TL_5 ,
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||||
TL_3 ,
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||||
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||||
#elif 0
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||||
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||||
// nasty one - doesn't solve
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||||
TL_6 ,
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||||
TL_3 ,
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||||
TL_SPACE ,
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TL_4 ,
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||||
TL_8 ,
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TL_5 ,
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||||
TL_7 ,
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TL_2 ,
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||||
TL_1 ,
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||||
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#elif 0
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||||
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||||
// sent by email - does work though
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||||
TL_1 , TL_2 , TL_3 ,
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||||
TL_4 , TL_5 , TL_6 ,
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TL_8 , TL_7 , TL_SPACE ,
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||||
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||||
// from http://www.cs.utexas.edu/users/novak/asg-8p.html
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||||
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||||
//Goal: Easy: Medium: Hard: Worst:
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||||
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||||
//1 2 3 1 3 4 2 8 1 2 8 1 5 6 7
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||||
//8 4 8 6 2 4 3 4 6 3 4 8
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||||
//7 6 5 7 5 7 6 5 7 5 3 2 1
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||||
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||||
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||||
#elif 0
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||||
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||||
// easy 5
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||||
TL_1 ,
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||||
TL_3 ,
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TL_4 ,
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||||
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TL_8 ,
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TL_6 ,
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TL_2 ,
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||||
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||||
TL_7 ,
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TL_SPACE ,
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||||
TL_5 ,
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||||
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||||
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#elif 0
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// medium 9
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TL_2 ,
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TL_8 ,
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TL_1 ,
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||||
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||||
TL_SPACE ,
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||||
TL_4 ,
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||||
TL_3 ,
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||||
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||||
TL_7 ,
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||||
TL_6 ,
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||||
TL_5 ,
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||||
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||||
#elif 0
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||||
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||||
// hard 12
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||||
TL_2 ,
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||||
TL_8 ,
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||||
TL_1 ,
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||||
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||||
TL_4 ,
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||||
TL_6 ,
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||||
TL_3 ,
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||||
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||||
TL_SPACE ,
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||||
TL_7 ,
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TL_5 ,
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||||
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#elif 0
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// worst 30
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||||
TL_5 ,
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TL_6 ,
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||||
TL_7 ,
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||||
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||||
TL_4 ,
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||||
TL_SPACE ,
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||||
TL_8 ,
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||||
|
||||
TL_3 ,
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||||
TL_2 ,
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||||
TL_1 ,
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||||
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||||
#elif 0
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||||
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||||
// 123
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||||
// 784
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||||
// 65
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||||
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||||
// two move simple board
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||||
TL_1 ,
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||||
TL_2 ,
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||||
TL_3 ,
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||||
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||||
TL_7 ,
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||||
TL_8 ,
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||||
TL_4 ,
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||||
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||||
TL_SPACE ,
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||||
TL_6 ,
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||||
TL_5 ,
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||||
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||||
#elif 0
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||||
// a1 b2 c3 d4 e5 f6 g7 h8
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||||
//C3,Blank,H8,A1,G8,F6,E5,D4,B2
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||||
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||||
TL_3 ,
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||||
TL_SPACE ,
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||||
TL_8 ,
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||||
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||||
TL_1 ,
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||||
TL_8 ,
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||||
TL_6 ,
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||||
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||||
TL_5 ,
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||||
TL_4 ,
|
||||
TL_2 ,
|
||||
|
||||
|
||||
#endif
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||||
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||||
};
|
||||
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||||
bool PuzzleState::IsSameState( PuzzleState &rhs )
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||||
{
|
||||
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||||
for( int i=0; i<(BOARD_HEIGHT*BOARD_WIDTH); i++ )
|
||||
{
|
||||
if( tiles[i] != rhs.tiles[i] )
|
||||
{
|
||||
return false;
|
||||
}
|
||||
}
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||||
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||||
return true;
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||||
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||||
}
|
||||
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void PuzzleState::PrintNodeInfo()
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||||
{
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||||
char str[100];
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sprintf( str, "%c %c %c\n%c %c %c\n%c %c %c\n",
|
||||
tiles[0] + '0',
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||||
tiles[1] + '0',
|
||||
tiles[2] + '0',
|
||||
tiles[3] + '0',
|
||||
tiles[4] + '0',
|
||||
tiles[5] + '0',
|
||||
tiles[6] + '0',
|
||||
tiles[7] + '0',
|
||||
tiles[8] + '0'
|
||||
);
|
||||
|
||||
cout << str;
|
||||
}
|
||||
|
||||
// Here's the heuristic function that estimates the distance from a PuzzleState
|
||||
// to the Goal.
|
||||
|
||||
float PuzzleState::GoalDistanceEstimate( PuzzleState &nodeGoal )
|
||||
{
|
||||
|
||||
// Nilsson's sequence score
|
||||
|
||||
int i, cx, cy, ax, ay, h = 0, s, t;
|
||||
|
||||
// given a tile this returns the tile that should be clockwise
|
||||
TILE correct_follower_to[ BOARD_WIDTH * BOARD_HEIGHT ] =
|
||||
{
|
||||
TL_SPACE, // always wrong
|
||||
TL_2,
|
||||
TL_3,
|
||||
TL_4,
|
||||
TL_5,
|
||||
TL_6,
|
||||
TL_7,
|
||||
TL_8,
|
||||
TL_1,
|
||||
};
|
||||
|
||||
// given a table index returns the index of the tile that is clockwise to it 3*3 only
|
||||
int clockwise_tile_of[ BOARD_WIDTH * BOARD_HEIGHT ] =
|
||||
{
|
||||
1,
|
||||
2, // 012
|
||||
5, // 345
|
||||
0, // 678
|
||||
-1, // never called with center square
|
||||
8,
|
||||
3,
|
||||
6,
|
||||
7
|
||||
};
|
||||
|
||||
int tile_x[ BOARD_WIDTH * BOARD_HEIGHT ] =
|
||||
{
|
||||
/* TL_SPACE */ 1,
|
||||
/* TL_1 */ 0,
|
||||
/* TL_2 */ 1,
|
||||
/* TL_3 */ 2,
|
||||
/* TL_4 */ 2,
|
||||
/* TL_5 */ 2,
|
||||
/* TL_6 */ 1,
|
||||
/* TL_7 */ 0,
|
||||
/* TL_8 */ 0,
|
||||
};
|
||||
|
||||
int tile_y[ BOARD_WIDTH * BOARD_HEIGHT ] =
|
||||
{
|
||||
/* TL_SPACE */ 1,
|
||||
/* TL_1 */ 0,
|
||||
/* TL_2 */ 0,
|
||||
/* TL_3 */ 0,
|
||||
/* TL_4 */ 1,
|
||||
/* TL_5 */ 2,
|
||||
/* TL_6 */ 2,
|
||||
/* TL_7 */ 2,
|
||||
/* TL_8 */ 1,
|
||||
};
|
||||
|
||||
s=0;
|
||||
|
||||
// score 1 point if centre is not correct
|
||||
if( tiles[(BOARD_HEIGHT*BOARD_WIDTH)/2] != nodeGoal.tiles[(BOARD_HEIGHT*BOARD_WIDTH)/2] )
|
||||
{
|
||||
s = 1;
|
||||
}
|
||||
|
||||
for( i=0; i<(BOARD_HEIGHT*BOARD_WIDTH); i++ )
|
||||
{
|
||||
// this loop adds up the totaldist element in h and
|
||||
// the sequence score in s
|
||||
|
||||
// the space does not count
|
||||
if( tiles[i] == TL_SPACE )
|
||||
{
|
||||
continue;
|
||||
}
|
||||
|
||||
// get correct x and y of this tile
|
||||
cx = tile_x[tiles[i]];
|
||||
cy = tile_y[tiles[i]];
|
||||
|
||||
// get actual
|
||||
ax = i % BOARD_WIDTH;
|
||||
ay = i / BOARD_WIDTH;
|
||||
|
||||
// add manhatten distance to h
|
||||
h += abs( cx-ax );
|
||||
h += abs( cy-ay );
|
||||
|
||||
// no s score for center tile
|
||||
if( (ax == (BOARD_WIDTH/2)) && (ay == (BOARD_HEIGHT/2)) )
|
||||
{
|
||||
continue;
|
||||
}
|
||||
|
||||
// score 2 points if not followed by successor
|
||||
if( correct_follower_to[ tiles[i] ] != tiles[ clockwise_tile_of[ i ] ] )
|
||||
{
|
||||
s += 2;
|
||||
}
|
||||
|
||||
|
||||
}
|
||||
|
||||
// mult by 3 and add to h
|
||||
t = h + (3*s);
|
||||
|
||||
return (float) t;
|
||||
|
||||
}
|
||||
|
||||
bool PuzzleState::IsGoal( PuzzleState &nodeGoal )
|
||||
{
|
||||
return IsSameState( nodeGoal );
|
||||
}
|
||||
|
||||
// Helper
|
||||
// Return the x and y position of the space tile
|
||||
void PuzzleState::GetSpacePosition( PuzzleState *pn, int *rx, int *ry )
|
||||
{
|
||||
int x,y;
|
||||
|
||||
for( y=0; y<BOARD_HEIGHT; y++ )
|
||||
{
|
||||
for( x=0; x<BOARD_WIDTH; x++ )
|
||||
{
|
||||
if( pn->tiles[(y*BOARD_WIDTH)+x] == TL_SPACE )
|
||||
{
|
||||
*rx = x;
|
||||
*ry = y;
|
||||
|
||||
return;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
assert( false && "Something went wrong. There's no space on the board" );
|
||||
|
||||
}
|
||||
|
||||
int PuzzleState::GetMap( int x, int y, TILE *tiles )
|
||||
{
|
||||
|
||||
if( x < 0 ||
|
||||
x >= BOARD_WIDTH ||
|
||||
y < 0 ||
|
||||
y >= BOARD_HEIGHT
|
||||
)
|
||||
return GM_OFF_BOARD;
|
||||
|
||||
if( tiles[(y*BOARD_WIDTH)+x] == TL_SPACE )
|
||||
{
|
||||
return GM_SPACE;
|
||||
}
|
||||
|
||||
return GM_TILE;
|
||||
}
|
||||
|
||||
// Given a node set of tiles and a set of tiles to move them into, do the move as if it was on a tile board
|
||||
// note : returns false if the board wasn't changed, and simply returns the tiles as they were in the target
|
||||
// spx and spy is the space position while tx and ty is the target move from position
|
||||
|
||||
bool PuzzleState::LegalMove( TILE *StartTiles, TILE *TargetTiles, int spx, int spy, int tx, int ty )
|
||||
{
|
||||
|
||||
int t;
|
||||
|
||||
if( GetMap( spx, spy, StartTiles ) == GM_SPACE )
|
||||
{
|
||||
if( GetMap( tx, ty, StartTiles ) == GM_TILE )
|
||||
{
|
||||
|
||||
// copy tiles
|
||||
for( t=0; t<(BOARD_HEIGHT*BOARD_WIDTH); t++ )
|
||||
{
|
||||
TargetTiles[t] = StartTiles[t];
|
||||
}
|
||||
|
||||
|
||||
TargetTiles[ (ty*BOARD_WIDTH)+tx ] = StartTiles[ (spy*BOARD_WIDTH)+spx ];
|
||||
TargetTiles[ (spy*BOARD_WIDTH)+spx ] = StartTiles[ (ty*BOARD_WIDTH)+tx ];
|
||||
|
||||
return true;
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
return false;
|
||||
|
||||
}
|
||||
|
||||
// This generates the successors to the given PuzzleState. It uses a helper function called
|
||||
// AddSuccessor to give the successors to the AStar class. The A* specific initialisation
|
||||
// is done for each node internally, so here you just set the state information that
|
||||
// is specific to the application
|
||||
bool PuzzleState::GetSuccessors( AStarSearch<PuzzleState> *astarsearch, PuzzleState *parent_node )
|
||||
{
|
||||
PuzzleState NewNode;
|
||||
|
||||
int sp_x,sp_y;
|
||||
|
||||
GetSpacePosition( this, &sp_x, &sp_y );
|
||||
|
||||
bool ret;
|
||||
|
||||
if( LegalMove( tiles, NewNode.tiles, sp_x, sp_y, sp_x, sp_y-1 ) == true )
|
||||
{
|
||||
ret = astarsearch->AddSuccessor( NewNode );
|
||||
|
||||
if( !ret ) return false;
|
||||
}
|
||||
|
||||
if( LegalMove( tiles, NewNode.tiles, sp_x, sp_y, sp_x, sp_y+1 ) == true )
|
||||
{
|
||||
ret = astarsearch->AddSuccessor( NewNode );
|
||||
|
||||
if( !ret ) return false;
|
||||
}
|
||||
|
||||
if( LegalMove( tiles, NewNode.tiles, sp_x, sp_y, sp_x-1, sp_y ) == true )
|
||||
{
|
||||
ret = astarsearch->AddSuccessor( NewNode );
|
||||
|
||||
if( !ret ) return false;
|
||||
}
|
||||
|
||||
if( LegalMove( tiles, NewNode.tiles, sp_x, sp_y, sp_x+1, sp_y ) == true )
|
||||
{
|
||||
ret = astarsearch->AddSuccessor( NewNode );
|
||||
|
||||
if( !ret ) return false;
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
// given this node, what does it cost to move to successor. In the case
|
||||
// of our map the answer is the map terrain value at this node since that is
|
||||
// conceptually where we're moving
|
||||
|
||||
float PuzzleState::GetCost( PuzzleState &successor )
|
||||
{
|
||||
return 1.0f; // I love it when life is simple
|
||||
|
||||
}
|
||||
|
||||
|
||||
// Main
|
||||
|
||||
int puzzle( int argc, char *argv[] )
|
||||
{
|
||||
|
||||
cout << "STL A* 8-puzzle solver implementation\n(C)2001 Justin Heyes-Jones\n";
|
||||
|
||||
if( argc > 1 )
|
||||
{
|
||||
int i = 0;
|
||||
int c;
|
||||
|
||||
while( (c = argv[1][i]) )
|
||||
{
|
||||
if( isdigit( c ) )
|
||||
{
|
||||
int num = (c - '0');
|
||||
|
||||
PuzzleState::g_start[i] = static_cast<PuzzleState::TILE>(num);
|
||||
|
||||
}
|
||||
|
||||
i++;
|
||||
}
|
||||
|
||||
|
||||
}
|
||||
|
||||
// Create an instance of the search class...
|
||||
|
||||
AStarSearch<PuzzleState> astarsearch;
|
||||
|
||||
int NumTimesToSearch = NUM_TIMES_TO_RUN_SEARCH;
|
||||
|
||||
while( NumTimesToSearch-- )
|
||||
{
|
||||
|
||||
// Create a start state
|
||||
PuzzleState nodeStart( PuzzleState::g_start );
|
||||
|
||||
// Define the goal state
|
||||
PuzzleState nodeEnd( PuzzleState::g_goal );
|
||||
|
||||
// Set Start and goal states
|
||||
astarsearch.SetStartAndGoalStates( nodeStart, nodeEnd );
|
||||
|
||||
unsigned int SearchState;
|
||||
|
||||
unsigned int SearchSteps = 0;
|
||||
|
||||
do
|
||||
{
|
||||
SearchState = astarsearch.SearchStep();
|
||||
|
||||
#if DEBUG_LISTS
|
||||
|
||||
float f,g,h;
|
||||
|
||||
cout << "Search step " << SearchSteps << endl;
|
||||
|
||||
cout << "Open:\n";
|
||||
PuzzleState *p = astarsearch.GetOpenListStart( f,g,h );
|
||||
while( p )
|
||||
{
|
||||
((PuzzleState *)p)->PrintNodeInfo();
|
||||
cout << "f: " << f << " g: " << g << " h: " << h << "\n\n";
|
||||
|
||||
p = astarsearch.GetOpenListNext( f,g,h );
|
||||
|
||||
}
|
||||
|
||||
cout << "Closed:\n";
|
||||
p = astarsearch.GetClosedListStart( f,g,h );
|
||||
while( p )
|
||||
{
|
||||
p->PrintNodeInfo();
|
||||
cout << "f: " << f << " g: " << g << " h: " << h << "\n\n";
|
||||
|
||||
p = astarsearch.GetClosedListNext( f,g,h );
|
||||
}
|
||||
|
||||
#endif
|
||||
|
||||
// Test cancel search
|
||||
#if 0
|
||||
int StepCount = astarsearch.GetStepCount();
|
||||
if( StepCount == 10 )
|
||||
{
|
||||
astarsearch.CancelSearch();
|
||||
}
|
||||
#endif
|
||||
SearchSteps++;
|
||||
}
|
||||
while( SearchState == AStarSearch<PuzzleState>::SEARCH_STATE_SEARCHING );
|
||||
|
||||
if( SearchState == AStarSearch<PuzzleState>::SEARCH_STATE_SUCCEEDED )
|
||||
{
|
||||
#if DISPLAY_SOLUTION_FORWARDS
|
||||
cout << "Search found goal state\n";
|
||||
#endif
|
||||
PuzzleState *node = astarsearch.GetSolutionStart();
|
||||
|
||||
#if DISPLAY_SOLUTION_FORWARDS
|
||||
cout << "Displaying solution\n";
|
||||
#endif
|
||||
int steps = 0;
|
||||
|
||||
#if DISPLAY_SOLUTION_FORWARDS
|
||||
node->PrintNodeInfo();
|
||||
cout << endl;
|
||||
#endif
|
||||
for( ;; )
|
||||
{
|
||||
node = astarsearch.GetSolutionNext();
|
||||
|
||||
if( !node )
|
||||
{
|
||||
break;
|
||||
}
|
||||
|
||||
#if DISPLAY_SOLUTION_FORWARDS
|
||||
node->PrintNodeInfo();
|
||||
cout << endl;
|
||||
#endif
|
||||
steps ++;
|
||||
|
||||
};
|
||||
|
||||
#if DISPLAY_SOLUTION_FORWARDS
|
||||
// todo move step count into main algorithm
|
||||
cout << "Solution steps " << steps << endl;
|
||||
#endif
|
||||
|
||||
////////////
|
||||
|
||||
node = astarsearch.GetSolutionEnd();
|
||||
|
||||
#if DISPLAY_SOLUTION_BACKWARDS
|
||||
cout << "Displaying reverse solution\n";
|
||||
#endif
|
||||
steps = 0;
|
||||
|
||||
node->PrintNodeInfo();
|
||||
cout << endl;
|
||||
for( ;; )
|
||||
{
|
||||
node = astarsearch.GetSolutionPrev();
|
||||
|
||||
if( !node )
|
||||
{
|
||||
break;
|
||||
}
|
||||
#if DISPLAY_SOLUTION_BACKWARDS
|
||||
node->PrintNodeInfo();
|
||||
cout << endl;
|
||||
#endif
|
||||
steps ++;
|
||||
|
||||
};
|
||||
|
||||
#if DISPLAY_SOLUTION_BACKWARDS
|
||||
cout << "Solution steps " << steps << endl;
|
||||
#endif
|
||||
|
||||
//////////////
|
||||
|
||||
// Once you're done with the solution you can free the nodes up
|
||||
astarsearch.FreeSolutionNodes();
|
||||
|
||||
}
|
||||
else if( SearchState == AStarSearch<PuzzleState>::SEARCH_STATE_FAILED )
|
||||
{
|
||||
#if DISPLAY_SOLUTION_INFO
|
||||
cout << "Search terminated. Did not find goal state\n";
|
||||
#endif
|
||||
}
|
||||
else if( SearchState == AStarSearch<PuzzleState>::SEARCH_STATE_OUT_OF_MEMORY )
|
||||
{
|
||||
#if DISPLAY_SOLUTION_INFO
|
||||
cout << "Search terminated. Out of memory\n";
|
||||
#endif
|
||||
}
|
||||
|
||||
|
||||
|
||||
// Display the number of loops the search went through
|
||||
#if DISPLAY_SOLUTION_INFO
|
||||
cout << "SearchSteps : " << astarsearch.GetStepCount() << endl;
|
||||
#endif
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
@ -0,0 +1,343 @@
|
||||
////////////////////////////////////////////////////////////////////////////////////////////////////////////////
|
||||
|
||||
// STL A* Search implementation
|
||||
// (C)2001 Justin Heyes-Jones
|
||||
//
|
||||
// Finding a path on a simple grid maze
|
||||
// This shows how to do shortest path finding using A*
|
||||
|
||||
////////////////////////////////////////////////////////////////////////////////////////////////////////////////
|
||||
|
||||
#include "stlastar.h" // See header for copyright and usage information
|
||||
|
||||
#include <iostream>
|
||||
#include <stdio.h>
|
||||
#include <math.h>
|
||||
|
||||
#define DEBUG_LISTS 0
|
||||
#define DEBUG_LIST_LENGTHS_ONLY 0
|
||||
|
||||
using namespace std;
|
||||
|
||||
// Global data
|
||||
|
||||
// The world map
|
||||
|
||||
const int MAP_WIDTH = 20;
|
||||
const int MAP_HEIGHT = 20;
|
||||
|
||||
int world_map[ MAP_WIDTH * MAP_HEIGHT ] =
|
||||
{
|
||||
|
||||
// 0001020304050607080910111213141516171819
|
||||
1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 00
|
||||
1,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,1, // 01
|
||||
1,9,9,1,1,9,9,9,1,9,1,9,1,9,1,9,9,9,1,1, // 02
|
||||
1,9,9,1,1,9,9,9,1,9,1,9,1,9,1,9,9,9,1,1, // 03
|
||||
1,9,1,1,1,1,9,9,1,9,1,9,1,1,1,1,9,9,1,1, // 04
|
||||
1,9,1,1,9,1,1,1,1,9,1,1,1,1,9,1,1,1,1,1, // 05
|
||||
1,9,9,9,9,1,1,1,1,1,1,9,9,9,9,1,1,1,1,1, // 06
|
||||
1,9,9,9,9,9,9,9,9,1,1,1,9,9,9,9,9,9,9,1, // 07
|
||||
1,9,1,1,1,1,1,1,1,1,1,9,1,1,1,1,1,1,1,1, // 08
|
||||
1,9,1,9,9,9,9,9,9,9,1,1,9,9,9,9,9,9,9,1, // 09
|
||||
1,9,1,1,1,1,9,1,1,9,1,1,1,1,1,1,1,1,1,1, // 10
|
||||
1,9,9,9,9,9,1,9,1,9,1,9,9,9,9,9,1,1,1,1, // 11
|
||||
1,9,1,9,1,9,9,9,1,9,1,9,1,9,1,9,9,9,1,1, // 12
|
||||
1,9,1,9,1,9,9,9,1,9,1,9,1,9,1,9,9,9,1,1, // 13
|
||||
1,9,1,1,1,1,9,9,1,9,1,9,1,1,1,1,9,9,1,1, // 14
|
||||
1,9,1,1,9,1,1,1,1,9,1,1,1,1,9,1,1,1,1,1, // 15
|
||||
1,9,9,9,9,1,1,1,1,1,1,9,9,9,9,1,1,1,1,1, // 16
|
||||
1,1,9,9,9,9,9,9,9,1,1,1,9,9,9,1,9,9,9,9, // 17
|
||||
1,9,1,1,1,1,1,1,1,1,1,9,1,1,1,1,1,1,1,1, // 18
|
||||
1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 19
|
||||
|
||||
};
|
||||
|
||||
// map helper functions
|
||||
|
||||
int GetMap( int x, int y )
|
||||
{
|
||||
if( x < 0 ||
|
||||
x >= MAP_WIDTH ||
|
||||
y < 0 ||
|
||||
y >= MAP_HEIGHT
|
||||
)
|
||||
{
|
||||
return 9;
|
||||
}
|
||||
|
||||
return world_map[(y*MAP_WIDTH)+x];
|
||||
}
|
||||
|
||||
|
||||
|
||||
// Definitions
|
||||
|
||||
class MapSearchNode
|
||||
{
|
||||
public:
|
||||
int x; // the (x,y) positions of the node
|
||||
int y;
|
||||
|
||||
MapSearchNode() { x = y = 0; }
|
||||
MapSearchNode( int px, int py ) { x=px; y=py; }
|
||||
|
||||
float GoalDistanceEstimate( MapSearchNode &nodeGoal );
|
||||
bool IsGoal( MapSearchNode &nodeGoal );
|
||||
bool GetSuccessors( AStarSearch<MapSearchNode> *astarsearch, MapSearchNode *parent_node );
|
||||
float GetCost( MapSearchNode &successor );
|
||||
bool IsSameState( MapSearchNode &rhs );
|
||||
|
||||
void PrintNodeInfo();
|
||||
|
||||
|
||||
};
|
||||
|
||||
bool MapSearchNode::IsSameState( MapSearchNode &rhs )
|
||||
{
|
||||
|
||||
// same state in a maze search is simply when (x,y) are the same
|
||||
if( (x == rhs.x) &&
|
||||
(y == rhs.y) )
|
||||
{
|
||||
return true;
|
||||
}
|
||||
else
|
||||
{
|
||||
return false;
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
void MapSearchNode::PrintNodeInfo()
|
||||
{
|
||||
char str[100];
|
||||
sprintf( str, "Node position : (%d,%d)\n", x,y );
|
||||
|
||||
cout << str;
|
||||
}
|
||||
|
||||
// Here's the heuristic function that estimates the distance from a Node
|
||||
// to the Goal.
|
||||
|
||||
float MapSearchNode::GoalDistanceEstimate( MapSearchNode &nodeGoal )
|
||||
{
|
||||
return abs(x - nodeGoal.x) + abs(y - nodeGoal.y);
|
||||
}
|
||||
|
||||
bool MapSearchNode::IsGoal( MapSearchNode &nodeGoal )
|
||||
{
|
||||
|
||||
if( (x == nodeGoal.x) &&
|
||||
(y == nodeGoal.y) )
|
||||
{
|
||||
return true;
|
||||
}
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
// This generates the successors to the given Node. It uses a helper function called
|
||||
// AddSuccessor to give the successors to the AStar class. The A* specific initialisation
|
||||
// is done for each node internally, so here you just set the state information that
|
||||
// is specific to the application
|
||||
bool MapSearchNode::GetSuccessors( AStarSearch<MapSearchNode> *astarsearch, MapSearchNode *parent_node )
|
||||
{
|
||||
|
||||
int parent_x = -1;
|
||||
int parent_y = -1;
|
||||
|
||||
if( parent_node )
|
||||
{
|
||||
parent_x = parent_node->x;
|
||||
parent_y = parent_node->y;
|
||||
}
|
||||
|
||||
|
||||
MapSearchNode NewNode;
|
||||
|
||||
// push each possible move except allowing the search to go backwards
|
||||
|
||||
if( (GetMap( x-1, y ) < 9)
|
||||
&& !((parent_x == x-1) && (parent_y == y))
|
||||
)
|
||||
{
|
||||
NewNode = MapSearchNode( x-1, y );
|
||||
astarsearch->AddSuccessor( NewNode );
|
||||
}
|
||||
|
||||
if( (GetMap( x, y-1 ) < 9)
|
||||
&& !((parent_x == x) && (parent_y == y-1))
|
||||
)
|
||||
{
|
||||
NewNode = MapSearchNode( x, y-1 );
|
||||
astarsearch->AddSuccessor( NewNode );
|
||||
}
|
||||
|
||||
if( (GetMap( x+1, y ) < 9)
|
||||
&& !((parent_x == x+1) && (parent_y == y))
|
||||
)
|
||||
{
|
||||
NewNode = MapSearchNode( x+1, y );
|
||||
astarsearch->AddSuccessor( NewNode );
|
||||
}
|
||||
|
||||
|
||||
if( (GetMap( x, y+1 ) < 9)
|
||||
&& !((parent_x == x) && (parent_y == y+1))
|
||||
)
|
||||
{
|
||||
NewNode = MapSearchNode( x, y+1 );
|
||||
astarsearch->AddSuccessor( NewNode );
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
// given this node, what does it cost to move to successor. In the case
|
||||
// of our map the answer is the map terrain value at this node since that is
|
||||
// conceptually where we're moving
|
||||
|
||||
float MapSearchNode::GetCost( MapSearchNode &successor )
|
||||
{
|
||||
return (float) GetMap( x, y );
|
||||
}
|
||||
|
||||
|
||||
// Main
|
||||
|
||||
int findpath( int argc, char *argv[] )
|
||||
{
|
||||
|
||||
cout << "STL A* Search implementation\n(C)2001 Justin Heyes-Jones\n";
|
||||
|
||||
// Our sample problem defines the world as a 2d array representing a terrain
|
||||
// Each element contains an integer from 0 to 5 which indicates the cost
|
||||
// of travel across the terrain. Zero means the least possible difficulty
|
||||
// in travelling (think ice rink if you can skate) whilst 5 represents the
|
||||
// most difficult. 9 indicates that we cannot pass.
|
||||
|
||||
// Create an instance of the search class...
|
||||
|
||||
AStarSearch<MapSearchNode> astarsearch;
|
||||
|
||||
unsigned int SearchCount = 0;
|
||||
|
||||
const unsigned int NumSearches = 1;
|
||||
|
||||
while(SearchCount < NumSearches)
|
||||
{
|
||||
|
||||
// Create a start state
|
||||
MapSearchNode nodeStart;
|
||||
nodeStart.x = rand()%MAP_WIDTH;
|
||||
nodeStart.y = rand()%MAP_HEIGHT;
|
||||
|
||||
// Define the goal state
|
||||
MapSearchNode nodeEnd;
|
||||
nodeEnd.x = rand()%MAP_WIDTH;
|
||||
nodeEnd.y = rand()%MAP_HEIGHT;
|
||||
|
||||
// Set Start and goal states
|
||||
|
||||
astarsearch.SetStartAndGoalStates( nodeStart, nodeEnd );
|
||||
|
||||
unsigned int SearchState;
|
||||
unsigned int SearchSteps = 0;
|
||||
|
||||
do
|
||||
{
|
||||
SearchState = astarsearch.SearchStep();
|
||||
|
||||
SearchSteps++;
|
||||
|
||||
#if DEBUG_LISTS
|
||||
|
||||
cout << "Steps:" << SearchSteps << "\n";
|
||||
|
||||
int len = 0;
|
||||
|
||||
cout << "Open:\n";
|
||||
MapSearchNode *p = astarsearch.GetOpenListStart();
|
||||
while( p )
|
||||
{
|
||||
len++;
|
||||
#if !DEBUG_LIST_LENGTHS_ONLY
|
||||
((MapSearchNode *)p)->PrintNodeInfo();
|
||||
#endif
|
||||
p = astarsearch.GetOpenListNext();
|
||||
|
||||
}
|
||||
|
||||
cout << "Open list has " << len << " nodes\n";
|
||||
|
||||
len = 0;
|
||||
|
||||
cout << "Closed:\n";
|
||||
p = astarsearch.GetClosedListStart();
|
||||
while( p )
|
||||
{
|
||||
len++;
|
||||
#if !DEBUG_LIST_LENGTHS_ONLY
|
||||
p->PrintNodeInfo();
|
||||
#endif
|
||||
p = astarsearch.GetClosedListNext();
|
||||
}
|
||||
|
||||
cout << "Closed list has " << len << " nodes\n";
|
||||
#endif
|
||||
|
||||
}
|
||||
while( SearchState == AStarSearch<MapSearchNode>::SEARCH_STATE_SEARCHING );
|
||||
|
||||
if( SearchState == AStarSearch<MapSearchNode>::SEARCH_STATE_SUCCEEDED )
|
||||
{
|
||||
cout << "Search found goal state\n";
|
||||
|
||||
MapSearchNode *node = astarsearch.GetSolutionStart();
|
||||
|
||||
#if DISPLAY_SOLUTION
|
||||
cout << "Displaying solution\n";
|
||||
#endif
|
||||
int steps = 0;
|
||||
|
||||
node->PrintNodeInfo();
|
||||
for( ;; )
|
||||
{
|
||||
node = astarsearch.GetSolutionNext();
|
||||
|
||||
if( !node )
|
||||
{
|
||||
break;
|
||||
}
|
||||
|
||||
node->PrintNodeInfo();
|
||||
steps ++;
|
||||
|
||||
};
|
||||
|
||||
cout << "Solution steps " << steps << endl;
|
||||
|
||||
// Once you're done with the solution you can free the nodes up
|
||||
astarsearch.FreeSolutionNodes();
|
||||
|
||||
|
||||
}
|
||||
else if( SearchState == AStarSearch<MapSearchNode>::SEARCH_STATE_FAILED )
|
||||
{
|
||||
cout << "Search terminated. Did not find goal state\n";
|
||||
|
||||
}
|
||||
|
||||
// Display the number of loops the search went through
|
||||
cout << "SearchSteps : " << SearchSteps << "\n";
|
||||
|
||||
SearchCount ++;
|
||||
|
||||
astarsearch.EnsureMemoryFreed();
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
////////////////////////////////////////////////////////////////////////////////////////////////////////////////
|
@ -0,0 +1,252 @@
|
||||
/*
|
||||
|
||||
A* Algorithm Implementation using STL is
|
||||
Copyright (C)2001-2005 Justin Heyes-Jones
|
||||
|
||||
Permission is given by the author to freely redistribute and
|
||||
include this code in any program as long as this credit is
|
||||
given where due.
|
||||
|
||||
COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS,
|
||||
WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED,
|
||||
INCLUDING, WITHOUT LIMITATION, WARRANTIES THAT THE COVERED CODE
|
||||
IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
|
||||
OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND
|
||||
PERFORMANCE OF THE COVERED CODE IS WITH YOU. SHOULD ANY COVERED
|
||||
CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT THE INITIAL
|
||||
DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY
|
||||
NECESSARY SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF
|
||||
WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE. NO USE
|
||||
OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
|
||||
THIS DISCLAIMER.
|
||||
|
||||
Use at your own risk!
|
||||
|
||||
|
||||
|
||||
FixedSizeAllocator class
|
||||
Copyright 2001 Justin Heyes-Jones
|
||||
|
||||
This class is a constant time O(1) memory manager for objects of
|
||||
a specified type. The type is specified using a template class.
|
||||
|
||||
Memory is allocated from a fixed size buffer which you can specify in the
|
||||
class constructor or use the default.
|
||||
|
||||
Using GetFirst and GetNext it is possible to iterate through the elements
|
||||
one by one, and this would be the most common use for the class.
|
||||
|
||||
I would suggest using this class when you want O(1) add and delete
|
||||
and you don't do much searching, which would be O(n). Structures such as binary
|
||||
trees can be used instead to get O(logn) access time.
|
||||
|
||||
*/
|
||||
|
||||
#ifndef FSA_H
|
||||
#define FSA_H
|
||||
|
||||
#include <string.h>
|
||||
#include <stdio.h>
|
||||
|
||||
template <class USER_TYPE> class FixedSizeAllocator
|
||||
{
|
||||
|
||||
public:
|
||||
// Constants
|
||||
enum
|
||||
{
|
||||
FSA_DEFAULT_SIZE = 100
|
||||
};
|
||||
|
||||
// This class enables us to transparently manage the extra data
|
||||
// needed to enable the user class to form part of the double-linked
|
||||
// list class
|
||||
struct FSA_ELEMENT
|
||||
{
|
||||
USER_TYPE UserType;
|
||||
|
||||
FSA_ELEMENT *pPrev;
|
||||
FSA_ELEMENT *pNext;
|
||||
};
|
||||
|
||||
public: // methods
|
||||
FixedSizeAllocator( unsigned int MaxElements = FSA_DEFAULT_SIZE ) :
|
||||
m_pFirstUsed( NULL ),
|
||||
m_MaxElements( MaxElements )
|
||||
{
|
||||
// Allocate enough memory for the maximum number of elements
|
||||
|
||||
char *pMem = new char[ m_MaxElements * sizeof(FSA_ELEMENT) ];
|
||||
|
||||
m_pMemory = (FSA_ELEMENT *) pMem;
|
||||
|
||||
// Set the free list first pointer
|
||||
m_pFirstFree = m_pMemory;
|
||||
|
||||
// Clear the memory
|
||||
memset( m_pMemory, 0, sizeof( FSA_ELEMENT ) * m_MaxElements );
|
||||
|
||||
// Point at first element
|
||||
FSA_ELEMENT *pElement = m_pFirstFree;
|
||||
|
||||
// Set the double linked free list
|
||||
for( unsigned int i=0; i<m_MaxElements; i++ )
|
||||
{
|
||||
pElement->pPrev = pElement-1;
|
||||
pElement->pNext = pElement+1;
|
||||
|
||||
pElement++;
|
||||
}
|
||||
|
||||
// first element should have a null prev
|
||||
m_pFirstFree->pPrev = NULL;
|
||||
// last element should have a null next
|
||||
(pElement-1)->pNext = NULL;
|
||||
|
||||
}
|
||||
|
||||
|
||||
~FixedSizeAllocator()
|
||||
{
|
||||
// Free up the memory
|
||||
delete [] (char *) m_pMemory;
|
||||
}
|
||||
|
||||
// Allocate a new USER_TYPE and return a pointer to it
|
||||
USER_TYPE *alloc()
|
||||
{
|
||||
|
||||
FSA_ELEMENT *pNewNode = NULL;
|
||||
|
||||
if( !m_pFirstFree )
|
||||
{
|
||||
return NULL;
|
||||
}
|
||||
else
|
||||
{
|
||||
pNewNode = m_pFirstFree;
|
||||
m_pFirstFree = pNewNode->pNext;
|
||||
|
||||
// if the new node points to another free node then
|
||||
// change that nodes prev free pointer...
|
||||
if( pNewNode->pNext )
|
||||
{
|
||||
pNewNode->pNext->pPrev = NULL;
|
||||
}
|
||||
|
||||
// node is now on the used list
|
||||
|
||||
pNewNode->pPrev = NULL; // the allocated node is always first in the list
|
||||
|
||||
if( m_pFirstUsed == NULL )
|
||||
{
|
||||
pNewNode->pNext = NULL; // no other nodes
|
||||
}
|
||||
else
|
||||
{
|
||||
m_pFirstUsed->pPrev = pNewNode; // insert this at the head of the used list
|
||||
pNewNode->pNext = m_pFirstUsed;
|
||||
}
|
||||
|
||||
m_pFirstUsed = pNewNode;
|
||||
}
|
||||
|
||||
return reinterpret_cast<USER_TYPE*>(pNewNode);
|
||||
}
|
||||
|
||||
// Free the given user type
|
||||
// For efficiency I don't check whether the user_data is a valid
|
||||
// pointer that was allocated. I may add some debug only checking
|
||||
// (To add the debug check you'd need to make sure the pointer is in
|
||||
// the m_pMemory area and is pointing at the start of a node)
|
||||
void free( USER_TYPE *user_data )
|
||||
{
|
||||
FSA_ELEMENT *pNode = reinterpret_cast<FSA_ELEMENT*>(user_data);
|
||||
|
||||
// manage used list, remove this node from it
|
||||
if( pNode->pPrev )
|
||||
{
|
||||
pNode->pPrev->pNext = pNode->pNext;
|
||||
}
|
||||
else
|
||||
{
|
||||
// this handles the case that we delete the first node in the used list
|
||||
m_pFirstUsed = pNode->pNext;
|
||||
}
|
||||
|
||||
if( pNode->pNext )
|
||||
{
|
||||
pNode->pNext->pPrev = pNode->pPrev;
|
||||
}
|
||||
|
||||
// add to free list
|
||||
if( m_pFirstFree == NULL )
|
||||
{
|
||||
// free list was empty
|
||||
m_pFirstFree = pNode;
|
||||
pNode->pPrev = NULL;
|
||||
pNode->pNext = NULL;
|
||||
}
|
||||
else
|
||||
{
|
||||
// Add this node at the start of the free list
|
||||
m_pFirstFree->pPrev = pNode;
|
||||
pNode->pNext = m_pFirstFree;
|
||||
m_pFirstFree = pNode;
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
// For debugging this displays both lists (using the prev/next list pointers)
|
||||
void Debug()
|
||||
{
|
||||
printf( "free list " );
|
||||
|
||||
FSA_ELEMENT *p = m_pFirstFree;
|
||||
while( p )
|
||||
{
|
||||
printf( "%x!%x ", p->pPrev, p->pNext );
|
||||
p = p->pNext;
|
||||
}
|
||||
printf( "\n" );
|
||||
|
||||
printf( "used list " );
|
||||
|
||||
p = m_pFirstUsed;
|
||||
while( p )
|
||||
{
|
||||
printf( "%x!%x ", p->pPrev, p->pNext );
|
||||
p = p->pNext;
|
||||
}
|
||||
printf( "\n" );
|
||||
}
|
||||
|
||||
// Iterators
|
||||
|
||||
USER_TYPE *GetFirst()
|
||||
{
|
||||
return reinterpret_cast<USER_TYPE *>(m_pFirstUsed);
|
||||
}
|
||||
|
||||
USER_TYPE *GetNext( USER_TYPE *node )
|
||||
{
|
||||
return reinterpret_cast<USER_TYPE *>
|
||||
(
|
||||
(reinterpret_cast<FSA_ELEMENT *>(node))->pNext
|
||||
);
|
||||
}
|
||||
|
||||
public: // data
|
||||
|
||||
private: // methods
|
||||
|
||||
private: // data
|
||||
|
||||
FSA_ELEMENT *m_pFirstFree;
|
||||
FSA_ELEMENT *m_pFirstUsed;
|
||||
unsigned int m_MaxElements;
|
||||
FSA_ELEMENT *m_pMemory;
|
||||
|
||||
};
|
||||
|
||||
#endif // defined FSA_H
|
@ -0,0 +1,315 @@
|
||||
////////////////////////////////////////////////////////////////////////////////////////////////////////////////
|
||||
// This example code illustrate how to use STL A* Search implementation to find the minimum path between two
|
||||
// cities given a map. The example is taken from the book AI: A Modern Approach, 3rd Ed., by Russel, where a map
|
||||
// of Romania is given. The target node is Bucharest, and the user can specify the initial city from which the
|
||||
// search algorithm will start looking for the minimum path to Bucharest.
|
||||
//
|
||||
// Usage: min_path_to_Bucharest <start city name>
|
||||
// Example:
|
||||
// min_path_to_Bucharest Arad
|
||||
//
|
||||
// Thanks to Rasoul Mojtahedzadeh for this contribution
|
||||
// Mojtahedzadeh _atsign_ gmail com
|
||||
//
|
||||
// Please note that this exercise is academic in nature and that the distances between the cities may not be
|
||||
// correct compared to the latitude and longnitude differences in real life. Thanks to parthi2929 for noticing
|
||||
// this issue. In a real application you would use some kind of exact x,y position of each city in order to get
|
||||
// accurate heuristics. In fact, that is part of the point of this example, in the book you will see Norvig
|
||||
// mention that the algorithm does some backtracking because the heuristic is not accurate (yet still admissable).
|
||||
////////////////////////////////////////////////////////////////////////////////////////////////////////////////
|
||||
#include "stlastar.h"
|
||||
#include <iostream>
|
||||
#include <string>
|
||||
#include <vector>
|
||||
#include <stdio.h>
|
||||
|
||||
#define DEBUG_LISTS 0
|
||||
#define DEBUG_LIST_LENGTHS_ONLY 0
|
||||
|
||||
using namespace std;
|
||||
|
||||
const int MAX_CITIES = 20;
|
||||
|
||||
enum ENUM_CITIES{Arad=0, Bucharest, Craiova, Drobeta, Eforie, Fagaras, Giurgiu, Hirsova, Iasi, Lugoj, Mehadia, Neamt, Oradea, Pitesti, RimnicuVilcea, Sibiu, Timisoara, Urziceni, Vaslui, Zerind};
|
||||
vector<string> CityNames(MAX_CITIES);
|
||||
float RomaniaMap[MAX_CITIES][MAX_CITIES];
|
||||
|
||||
class PathSearchNode
|
||||
{
|
||||
public:
|
||||
|
||||
ENUM_CITIES city;
|
||||
|
||||
PathSearchNode() { city = Arad; }
|
||||
PathSearchNode( ENUM_CITIES in ) { city = in; }
|
||||
|
||||
float GoalDistanceEstimate( PathSearchNode &nodeGoal );
|
||||
bool IsGoal( PathSearchNode &nodeGoal );
|
||||
bool GetSuccessors( AStarSearch<PathSearchNode> *astarsearch, PathSearchNode *parent_node );
|
||||
float GetCost( PathSearchNode &successor );
|
||||
bool IsSameState( PathSearchNode &rhs );
|
||||
|
||||
void PrintNodeInfo();
|
||||
};
|
||||
|
||||
// check if "this" node is the same as "rhs" node
|
||||
bool PathSearchNode::IsSameState( PathSearchNode &rhs )
|
||||
{
|
||||
if(city == rhs.city) return(true);
|
||||
return(false);
|
||||
}
|
||||
|
||||
// Euclidean distance between "this" node city and Bucharest
|
||||
// Note: Numbers are taken from the book
|
||||
float PathSearchNode::GoalDistanceEstimate( PathSearchNode &nodeGoal )
|
||||
{
|
||||
// goal is always Bucharest!
|
||||
switch(city)
|
||||
{
|
||||
case Arad: return 366; break;
|
||||
case Bucharest: return 0; break;
|
||||
case Craiova: return 160; break;
|
||||
case Drobeta: return 242; break;
|
||||
case Eforie: return 161; break;
|
||||
case Fagaras: return 176; break;
|
||||
case Giurgiu: return 77; break;
|
||||
case Hirsova: return 151; break;
|
||||
case Iasi: return 226; break;
|
||||
case Lugoj: return 244; break;
|
||||
case Mehadia: return 241; break;
|
||||
case Neamt: return 234; break;
|
||||
case Oradea: return 380; break;
|
||||
case Pitesti: return 100; break;
|
||||
case RimnicuVilcea: return 193; break;
|
||||
case Sibiu: return 253; break;
|
||||
case Timisoara: return 329; break;
|
||||
case Urziceni: return 80; break;
|
||||
case Vaslui: return 199; break;
|
||||
case Zerind: return 374; break;
|
||||
}
|
||||
cerr << "ASSERT: city = " << CityNames[city] << endl;
|
||||
return 0;
|
||||
}
|
||||
|
||||
// check if "this" node is the goal node
|
||||
bool PathSearchNode::IsGoal( PathSearchNode &nodeGoal )
|
||||
{
|
||||
if( city == Bucharest ) return(true);
|
||||
return(false);
|
||||
}
|
||||
|
||||
// generates the successor nodes of "this" node
|
||||
bool PathSearchNode::GetSuccessors( AStarSearch<PathSearchNode> *astarsearch, PathSearchNode *parent_node )
|
||||
{
|
||||
PathSearchNode NewNode;
|
||||
for(int c=0; c<MAX_CITIES; c++)
|
||||
{
|
||||
if(RomaniaMap[city][c] < 0) continue;
|
||||
NewNode = PathSearchNode((ENUM_CITIES)c);
|
||||
astarsearch->AddSuccessor( NewNode );
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
// the cost of going from "this" node to the "successor" node
|
||||
float PathSearchNode::GetCost( PathSearchNode &successor )
|
||||
{
|
||||
return RomaniaMap[city][successor.city];
|
||||
}
|
||||
|
||||
// prints out information about the node
|
||||
void PathSearchNode::PrintNodeInfo()
|
||||
{
|
||||
cout << " " << CityNames[city] << "\n";
|
||||
}
|
||||
|
||||
// Main
|
||||
int min_path_to_Bucharest( int argc, char *argv[] )
|
||||
{
|
||||
// creating map of Romania
|
||||
for(int i=0; i<MAX_CITIES; i++)
|
||||
for(int j=0; j<MAX_CITIES; j++)
|
||||
RomaniaMap[i][j]=-1.0;
|
||||
|
||||
RomaniaMap[Arad][Sibiu]=140;
|
||||
RomaniaMap[Arad][Zerind]=75;
|
||||
RomaniaMap[Arad][Timisoara]=118;
|
||||
RomaniaMap[Bucharest][Giurgiu]=90;
|
||||
RomaniaMap[Bucharest][Urziceni]=85;
|
||||
RomaniaMap[Bucharest][Fagaras]=211;
|
||||
RomaniaMap[Bucharest][Pitesti]=101;
|
||||
RomaniaMap[Craiova][Drobeta]=120;
|
||||
RomaniaMap[Craiova][RimnicuVilcea]=146;
|
||||
RomaniaMap[Craiova][Pitesti]=138;
|
||||
RomaniaMap[Drobeta][Craiova]=120;
|
||||
RomaniaMap[Drobeta][Mehadia]=75;
|
||||
RomaniaMap[Eforie][Hirsova]=75;
|
||||
RomaniaMap[Fagaras][Bucharest]=211;
|
||||
RomaniaMap[Fagaras][Sibiu]=99;
|
||||
RomaniaMap[Giurgiu][Bucharest]=90;
|
||||
RomaniaMap[Hirsova][Eforie]=86;
|
||||
RomaniaMap[Hirsova][Urziceni]=98;
|
||||
RomaniaMap[Iasi][Vaslui]=92;
|
||||
RomaniaMap[Iasi][Neamt]=87;
|
||||
RomaniaMap[Lugoj][Timisoara]=111;
|
||||
RomaniaMap[Lugoj][Mehadia]=70;
|
||||
RomaniaMap[Mehadia][Lugoj]=70;
|
||||
RomaniaMap[Mehadia][Drobeta]=75;
|
||||
RomaniaMap[Neamt][Iasi]=87;
|
||||
RomaniaMap[Oradea][Zerind]=71;
|
||||
RomaniaMap[Oradea][Sibiu]=151;
|
||||
RomaniaMap[Pitesti][Bucharest]=101;
|
||||
RomaniaMap[Pitesti][RimnicuVilcea]=97;
|
||||
RomaniaMap[Pitesti][Craiova]=138;
|
||||
RomaniaMap[RimnicuVilcea][Pitesti]=97;
|
||||
RomaniaMap[RimnicuVilcea][Craiova]=146;
|
||||
RomaniaMap[RimnicuVilcea][Sibiu]=80;
|
||||
RomaniaMap[Sibiu][RimnicuVilcea]=80;
|
||||
RomaniaMap[Sibiu][Fagaras]=99;
|
||||
RomaniaMap[Sibiu][Oradea]=151;
|
||||
RomaniaMap[Sibiu][Arad]=140;
|
||||
RomaniaMap[Timisoara][Arad]=118;
|
||||
RomaniaMap[Timisoara][Lugoj]=111;
|
||||
RomaniaMap[Urziceni][Bucharest]=85;
|
||||
RomaniaMap[Urziceni][Hirsova]=98;
|
||||
RomaniaMap[Urziceni][Vaslui]=142;
|
||||
RomaniaMap[Vaslui][Urziceni]=142;
|
||||
RomaniaMap[Vaslui][Iasi]=92;
|
||||
RomaniaMap[Zerind][Arad]=75;
|
||||
RomaniaMap[Zerind][Oradea]=71;
|
||||
|
||||
// City names
|
||||
CityNames[Arad].assign("Arad");
|
||||
CityNames[Bucharest].assign("Bucharest");
|
||||
CityNames[Craiova].assign("Craiova");
|
||||
CityNames[Drobeta].assign("Drobeta");
|
||||
CityNames[Eforie].assign("Eforie");
|
||||
CityNames[Fagaras].assign("Fagaras");
|
||||
CityNames[Giurgiu].assign("Giurgiu");
|
||||
CityNames[Hirsova].assign("Hirsova");
|
||||
CityNames[Iasi].assign("Iasi");
|
||||
CityNames[Lugoj].assign("Lugoj");
|
||||
CityNames[Mehadia].assign("Mehadia");
|
||||
CityNames[Neamt].assign("Neamt");
|
||||
CityNames[Oradea].assign("Oradea");
|
||||
CityNames[Pitesti].assign("Pitesti");
|
||||
CityNames[RimnicuVilcea].assign("RimnicuVilcea");
|
||||
CityNames[Sibiu].assign("Sibiu");
|
||||
CityNames[Timisoara].assign("Timisoara");
|
||||
CityNames[Urziceni].assign("Urziceni");
|
||||
CityNames[Vaslui].assign("Vaslui");
|
||||
CityNames[Zerind].assign("Zerind");
|
||||
|
||||
ENUM_CITIES initCity = Arad;
|
||||
if(argc == 2)
|
||||
{
|
||||
bool found = false;
|
||||
for(size_t i=0; i<CityNames.size(); i++)
|
||||
if(CityNames[i].compare(argv[1])==0)
|
||||
{
|
||||
initCity = (ENUM_CITIES)i;
|
||||
found = true;
|
||||
break;
|
||||
}
|
||||
if(not found)
|
||||
{
|
||||
cout << "There is no city named "<<argv[1]<<" in the map!\n";
|
||||
return(1);
|
||||
}
|
||||
}
|
||||
|
||||
// An instance of A* search class
|
||||
AStarSearch<PathSearchNode> astarsearch;
|
||||
|
||||
unsigned int SearchCount = 0;
|
||||
const unsigned int NumSearches = 1;
|
||||
|
||||
while(SearchCount < NumSearches)
|
||||
{
|
||||
// Create a start state
|
||||
PathSearchNode nodeStart;
|
||||
nodeStart.city = initCity;
|
||||
|
||||
// Define the goal state, always Bucharest!
|
||||
PathSearchNode nodeEnd;
|
||||
nodeEnd.city = Bucharest;
|
||||
|
||||
// Set Start and goal states
|
||||
astarsearch.SetStartAndGoalStates( nodeStart, nodeEnd );
|
||||
|
||||
unsigned int SearchState;
|
||||
unsigned int SearchSteps = 0;
|
||||
|
||||
do
|
||||
{
|
||||
SearchState = astarsearch.SearchStep();
|
||||
SearchSteps++;
|
||||
|
||||
#if DEBUG_LISTS
|
||||
|
||||
cout << "Steps:" << SearchSteps << "\n";
|
||||
|
||||
int len = 0;
|
||||
|
||||
cout << "Open:\n";
|
||||
PathSearchNode *p = astarsearch.GetOpenListStart();
|
||||
while( p )
|
||||
{
|
||||
len++;
|
||||
#if !DEBUG_LIST_LENGTHS_ONLY
|
||||
((PathSearchNode *)p)->PrintNodeInfo();
|
||||
#endif
|
||||
p = astarsearch.GetOpenListNext();
|
||||
|
||||
}
|
||||
cout << "Open list has " << len << " nodes\n";
|
||||
|
||||
len = 0;
|
||||
|
||||
cout << "Closed:\n";
|
||||
p = astarsearch.GetClosedListStart();
|
||||
while( p )
|
||||
{
|
||||
len++;
|
||||
#if !DEBUG_LIST_LENGTHS_ONLY
|
||||
p->PrintNodeInfo();
|
||||
#endif
|
||||
p = astarsearch.GetClosedListNext();
|
||||
}
|
||||
|
||||
cout << "Closed list has " << len << " nodes\n";
|
||||
#endif
|
||||
|
||||
}
|
||||
while( SearchState == AStarSearch<PathSearchNode>::SEARCH_STATE_SEARCHING );
|
||||
|
||||
if( SearchState == AStarSearch<PathSearchNode>::SEARCH_STATE_SUCCEEDED )
|
||||
{
|
||||
cout << "Search found the goal state\n";
|
||||
PathSearchNode *node = astarsearch.GetSolutionStart();
|
||||
cout << "Displaying solution\n";
|
||||
int steps = 0;
|
||||
node->PrintNodeInfo();
|
||||
for( ;; )
|
||||
{
|
||||
node = astarsearch.GetSolutionNext();
|
||||
if( !node ) break;
|
||||
node->PrintNodeInfo();
|
||||
steps ++;
|
||||
};
|
||||
cout << "Solution steps " << steps << endl;
|
||||
// Once you're done with the solution you can free the nodes up
|
||||
astarsearch.FreeSolutionNodes();
|
||||
}
|
||||
else if( SearchState == AStarSearch<PathSearchNode>::SEARCH_STATE_FAILED )
|
||||
{
|
||||
cout << "Search terminated. Did not find goal state\n";
|
||||
}
|
||||
// Display the number of loops the search went through
|
||||
cout << "SearchSteps : " << SearchSteps << "\n";
|
||||
SearchCount ++;
|
||||
astarsearch.EnsureMemoryFreed();
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
@ -0,0 +1,833 @@
|
||||
/*
|
||||
A* Algorithm Implementation using STL is
|
||||
Copyright (C)2001-2005 Justin Heyes-Jones
|
||||
|
||||
Permission is given by the author to freely redistribute and
|
||||
include this code in any program as long as this credit is
|
||||
given where due.
|
||||
|
||||
COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS,
|
||||
WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED,
|
||||
INCLUDING, WITHOUT LIMITATION, WARRANTIES THAT THE COVERED CODE
|
||||
IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
|
||||
OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND
|
||||
PERFORMANCE OF THE COVERED CODE IS WITH YOU. SHOULD ANY COVERED
|
||||
CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT THE INITIAL
|
||||
DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY
|
||||
NECESSARY SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF
|
||||
WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE. NO USE
|
||||
OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
|
||||
THIS DISCLAIMER.
|
||||
|
||||
Use at your own risk!
|
||||
|
||||
*/
|
||||
|
||||
#ifndef STLASTAR_H
|
||||
#define STLASTAR_H
|
||||
// used for text debugging
|
||||
#include <iostream>
|
||||
#include <stdio.h>
|
||||
//#include <conio.h>
|
||||
#include <assert.h>
|
||||
|
||||
// stl includes
|
||||
#include <algorithm>
|
||||
#include <set>
|
||||
#include <vector>
|
||||
#include <cfloat>
|
||||
|
||||
using namespace std;
|
||||
|
||||
// fast fixed size memory allocator, used for fast node memory management
|
||||
#include "fsa.h"
|
||||
|
||||
// Fixed size memory allocator can be disabled to compare performance
|
||||
// Uses std new and delete instead if you turn it off
|
||||
#define USE_FSA_MEMORY 1
|
||||
|
||||
// disable warning that debugging information has lines that are truncated
|
||||
// occurs in stl headers
|
||||
#if defined(WIN32) && defined(_WINDOWS)
|
||||
#pragma warning( disable : 4786 )
|
||||
#endif
|
||||
|
||||
template <class T> class AStarState;
|
||||
|
||||
// The AStar search class. UserState is the users state space type
|
||||
template <class UserState> class AStarSearch
|
||||
{
|
||||
|
||||
public: // data
|
||||
|
||||
enum
|
||||
{
|
||||
SEARCH_STATE_NOT_INITIALISED,
|
||||
SEARCH_STATE_SEARCHING,
|
||||
SEARCH_STATE_SUCCEEDED,
|
||||
SEARCH_STATE_FAILED,
|
||||
SEARCH_STATE_OUT_OF_MEMORY,
|
||||
SEARCH_STATE_INVALID
|
||||
};
|
||||
|
||||
|
||||
// A node represents a possible state in the search
|
||||
// The user provided state type is included inside this type
|
||||
|
||||
public:
|
||||
|
||||
class Node
|
||||
{
|
||||
public:
|
||||
|
||||
Node *parent; // used during the search to record the parent of successor nodes
|
||||
Node *child; // used after the search for the application to view the search in reverse
|
||||
|
||||
float g; // cost of this node + it's predecessors
|
||||
float h; // heuristic estimate of distance to goal
|
||||
float f; // sum of cumulative cost of predecessors and self and heuristic
|
||||
|
||||
Node() :
|
||||
parent( 0 ),
|
||||
child( 0 ),
|
||||
g( 0.0f ),
|
||||
h( 0.0f ),
|
||||
f( 0.0f )
|
||||
{
|
||||
}
|
||||
|
||||
UserState m_UserState;
|
||||
};
|
||||
|
||||
|
||||
// For sorting the heap the STL needs compare function that lets us compare
|
||||
// the f value of two nodes
|
||||
|
||||
class HeapCompare_f
|
||||
{
|
||||
public:
|
||||
|
||||
bool operator() ( const Node *x, const Node *y ) const
|
||||
{
|
||||
return x->f > y->f;
|
||||
}
|
||||
};
|
||||
|
||||
|
||||
public: // methods
|
||||
|
||||
|
||||
// constructor just initialises private data
|
||||
AStarSearch() :
|
||||
m_State( SEARCH_STATE_NOT_INITIALISED ),
|
||||
m_CurrentSolutionNode( NULL ),
|
||||
#if USE_FSA_MEMORY
|
||||
m_FixedSizeAllocator( 1000 ),
|
||||
#endif
|
||||
m_AllocateNodeCount(0),
|
||||
m_CancelRequest( false )
|
||||
{
|
||||
}
|
||||
|
||||
AStarSearch( int MaxNodes ) :
|
||||
m_State( SEARCH_STATE_NOT_INITIALISED ),
|
||||
m_CurrentSolutionNode( NULL ),
|
||||
#if USE_FSA_MEMORY
|
||||
m_FixedSizeAllocator( MaxNodes ),
|
||||
#endif
|
||||
m_AllocateNodeCount(0),
|
||||
m_CancelRequest( false )
|
||||
{
|
||||
}
|
||||
|
||||
// call at any time to cancel the search and free up all the memory
|
||||
void CancelSearch()
|
||||
{
|
||||
m_CancelRequest = true;
|
||||
}
|
||||
|
||||
// Set Start and goal states
|
||||
void SetStartAndGoalStates( UserState &Start, UserState &Goal )
|
||||
{
|
||||
m_CancelRequest = false;
|
||||
|
||||
m_Start = AllocateNode();
|
||||
m_Goal = AllocateNode();
|
||||
|
||||
assert((m_Start != NULL && m_Goal != NULL));
|
||||
|
||||
m_Start->m_UserState = Start;
|
||||
m_Goal->m_UserState = Goal;
|
||||
|
||||
m_State = SEARCH_STATE_SEARCHING;
|
||||
|
||||
// Initialise the AStar specific parts of the Start Node
|
||||
// The user only needs fill out the state information
|
||||
|
||||
m_Start->g = 0;
|
||||
m_Start->h = m_Start->m_UserState.GoalDistanceEstimate( m_Goal->m_UserState );
|
||||
m_Start->f = m_Start->g + m_Start->h;
|
||||
m_Start->parent = 0;
|
||||
|
||||
// Push the start node on the Open list
|
||||
|
||||
m_OpenList.push_back( m_Start ); // heap now unsorted
|
||||
|
||||
// Sort back element into heap
|
||||
push_heap( m_OpenList.begin(), m_OpenList.end(), HeapCompare_f() );
|
||||
|
||||
// Initialise counter for search steps
|
||||
m_Steps = 0;
|
||||
}
|
||||
|
||||
// Advances search one step
|
||||
unsigned int SearchStep()
|
||||
{
|
||||
// Firstly break if the user has not initialised the search
|
||||
assert( (m_State > SEARCH_STATE_NOT_INITIALISED) &&
|
||||
(m_State < SEARCH_STATE_INVALID) );
|
||||
|
||||
// Next I want it to be safe to do a searchstep once the search has succeeded...
|
||||
if( (m_State == SEARCH_STATE_SUCCEEDED) ||
|
||||
(m_State == SEARCH_STATE_FAILED)
|
||||
)
|
||||
{
|
||||
return m_State;
|
||||
}
|
||||
|
||||
// Failure is defined as emptying the open list as there is nothing left to
|
||||
// search...
|
||||
// New: Allow user abort
|
||||
if( m_OpenList.empty() || m_CancelRequest )
|
||||
{
|
||||
FreeAllNodes();
|
||||
m_State = SEARCH_STATE_FAILED;
|
||||
return m_State;
|
||||
}
|
||||
|
||||
// Incremement step count
|
||||
m_Steps ++;
|
||||
|
||||
// Pop the best node (the one with the lowest f)
|
||||
Node *n = m_OpenList.front(); // get pointer to the node
|
||||
pop_heap( m_OpenList.begin(), m_OpenList.end(), HeapCompare_f() );
|
||||
m_OpenList.pop_back();
|
||||
|
||||
// Check for the goal, once we pop that we're done
|
||||
if( n->m_UserState.IsGoal( m_Goal->m_UserState ) )
|
||||
{
|
||||
// The user is going to use the Goal Node he passed in
|
||||
// so copy the parent pointer of n
|
||||
m_Goal->parent = n->parent;
|
||||
m_Goal->g = n->g;
|
||||
|
||||
// A special case is that the goal was passed in as the start state
|
||||
// so handle that here
|
||||
if( false == n->m_UserState.IsSameState( m_Start->m_UserState ) )
|
||||
{
|
||||
FreeNode( n );
|
||||
|
||||
// set the child pointers in each node (except Goal which has no child)
|
||||
Node *nodeChild = m_Goal;
|
||||
Node *nodeParent = m_Goal->parent;
|
||||
|
||||
do
|
||||
{
|
||||
nodeParent->child = nodeChild;
|
||||
|
||||
nodeChild = nodeParent;
|
||||
nodeParent = nodeParent->parent;
|
||||
|
||||
}
|
||||
while( nodeChild != m_Start ); // Start is always the first node by definition
|
||||
|
||||
}
|
||||
|
||||
// delete nodes that aren't needed for the solution
|
||||
FreeUnusedNodes();
|
||||
|
||||
m_State = SEARCH_STATE_SUCCEEDED;
|
||||
|
||||
return m_State;
|
||||
}
|
||||
else // not goal
|
||||
{
|
||||
|
||||
// We now need to generate the successors of this node
|
||||
// The user helps us to do this, and we keep the new nodes in
|
||||
// m_Successors ...
|
||||
|
||||
m_Successors.clear(); // empty vector of successor nodes to n
|
||||
|
||||
// User provides this functions and uses AddSuccessor to add each successor of
|
||||
// node 'n' to m_Successors
|
||||
bool ret = n->m_UserState.GetSuccessors( this, n->parent ? &n->parent->m_UserState : NULL );
|
||||
|
||||
if( !ret )
|
||||
{
|
||||
|
||||
typename vector< Node * >::iterator successor;
|
||||
|
||||
// free the nodes that may previously have been added
|
||||
for( successor = m_Successors.begin(); successor != m_Successors.end(); successor ++ )
|
||||
{
|
||||
FreeNode( (*successor) );
|
||||
}
|
||||
|
||||
m_Successors.clear(); // empty vector of successor nodes to n
|
||||
|
||||
// free up everything else we allocated
|
||||
FreeNode( (n) );
|
||||
FreeAllNodes();
|
||||
|
||||
m_State = SEARCH_STATE_OUT_OF_MEMORY;
|
||||
return m_State;
|
||||
}
|
||||
|
||||
// Now handle each successor to the current node ...
|
||||
for( typename vector< Node * >::iterator successor = m_Successors.begin(); successor != m_Successors.end(); successor ++ )
|
||||
{
|
||||
|
||||
// The g value for this successor ...
|
||||
float newg = n->g + n->m_UserState.GetCost( (*successor)->m_UserState );
|
||||
|
||||
// Now we need to find whether the node is on the open or closed lists
|
||||
// If it is but the node that is already on them is better (lower g)
|
||||
// then we can forget about this successor
|
||||
|
||||
// First linear search of open list to find node
|
||||
|
||||
typename vector< Node * >::iterator openlist_result;
|
||||
|
||||
for( openlist_result = m_OpenList.begin(); openlist_result != m_OpenList.end(); openlist_result ++ )
|
||||
{
|
||||
if( (*openlist_result)->m_UserState.IsSameState( (*successor)->m_UserState ) )
|
||||
{
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
if( openlist_result != m_OpenList.end() )
|
||||
{
|
||||
|
||||
// we found this state on open
|
||||
|
||||
if( (*openlist_result)->g <= newg )
|
||||
{
|
||||
FreeNode( (*successor) );
|
||||
|
||||
// the one on Open is cheaper than this one
|
||||
continue;
|
||||
}
|
||||
}
|
||||
|
||||
typename vector< Node * >::iterator closedlist_result;
|
||||
|
||||
for( closedlist_result = m_ClosedList.begin(); closedlist_result != m_ClosedList.end(); closedlist_result ++ )
|
||||
{
|
||||
if( (*closedlist_result)->m_UserState.IsSameState( (*successor)->m_UserState ) )
|
||||
{
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
if( closedlist_result != m_ClosedList.end() )
|
||||
{
|
||||
|
||||
// we found this state on closed
|
||||
|
||||
if( (*closedlist_result)->g <= newg )
|
||||
{
|
||||
// the one on Closed is cheaper than this one
|
||||
FreeNode( (*successor) );
|
||||
|
||||
continue;
|
||||
}
|
||||
}
|
||||
|
||||
// This node is the best node so far with this particular state
|
||||
// so lets keep it and set up its AStar specific data ...
|
||||
|
||||
(*successor)->parent = n;
|
||||
(*successor)->g = newg;
|
||||
(*successor)->h = (*successor)->m_UserState.GoalDistanceEstimate( m_Goal->m_UserState );
|
||||
(*successor)->f = (*successor)->g + (*successor)->h;
|
||||
|
||||
// Successor in closed list
|
||||
// 1 - Update old version of this node in closed list
|
||||
// 2 - Move it from closed to open list
|
||||
// 3 - Sort heap again in open list
|
||||
|
||||
if( closedlist_result != m_ClosedList.end() )
|
||||
{
|
||||
// Update closed node with successor node AStar data
|
||||
//*(*closedlist_result) = *(*successor);
|
||||
(*closedlist_result)->parent = (*successor)->parent;
|
||||
(*closedlist_result)->g = (*successor)->g;
|
||||
(*closedlist_result)->h = (*successor)->h;
|
||||
(*closedlist_result)->f = (*successor)->f;
|
||||
|
||||
// Free successor node
|
||||
FreeNode( (*successor) );
|
||||
|
||||
// Push closed node into open list
|
||||
m_OpenList.push_back( (*closedlist_result) );
|
||||
|
||||
// Remove closed node from closed list
|
||||
m_ClosedList.erase( closedlist_result );
|
||||
|
||||
// Sort back element into heap
|
||||
push_heap( m_OpenList.begin(), m_OpenList.end(), HeapCompare_f() );
|
||||
|
||||
// Fix thanks to ...
|
||||
// Greg Douglas <gregdouglasmail@gmail.com>
|
||||
// who noticed that this code path was incorrect
|
||||
// Here we have found a new state which is already CLOSED
|
||||
|
||||
}
|
||||
|
||||
// Successor in open list
|
||||
// 1 - Update old version of this node in open list
|
||||
// 2 - sort heap again in open list
|
||||
|
||||
else if( openlist_result != m_OpenList.end() )
|
||||
{
|
||||
// Update open node with successor node AStar data
|
||||
//*(*openlist_result) = *(*successor);
|
||||
(*openlist_result)->parent = (*successor)->parent;
|
||||
(*openlist_result)->g = (*successor)->g;
|
||||
(*openlist_result)->h = (*successor)->h;
|
||||
(*openlist_result)->f = (*successor)->f;
|
||||
|
||||
// Free successor node
|
||||
FreeNode( (*successor) );
|
||||
|
||||
// re-make the heap
|
||||
// make_heap rather than sort_heap is an essential bug fix
|
||||
// thanks to Mike Ryynanen for pointing this out and then explaining
|
||||
// it in detail. sort_heap called on an invalid heap does not work
|
||||
make_heap( m_OpenList.begin(), m_OpenList.end(), HeapCompare_f() );
|
||||
}
|
||||
|
||||
// New successor
|
||||
// 1 - Move it from successors to open list
|
||||
// 2 - sort heap again in open list
|
||||
|
||||
else
|
||||
{
|
||||
// Push successor node into open list
|
||||
m_OpenList.push_back( (*successor) );
|
||||
|
||||
// Sort back element into heap
|
||||
push_heap( m_OpenList.begin(), m_OpenList.end(), HeapCompare_f() );
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
// push n onto Closed, as we have expanded it now
|
||||
|
||||
m_ClosedList.push_back( n );
|
||||
|
||||
} // end else (not goal so expand)
|
||||
|
||||
return m_State; // Succeeded bool is false at this point.
|
||||
|
||||
}
|
||||
|
||||
// User calls this to add a successor to a list of successors
|
||||
// when expanding the search frontier
|
||||
bool AddSuccessor( UserState &State )
|
||||
{
|
||||
Node *node = AllocateNode();
|
||||
|
||||
if( node )
|
||||
{
|
||||
node->m_UserState = State;
|
||||
|
||||
m_Successors.push_back( node );
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
// Free the solution nodes
|
||||
// This is done to clean up all used Node memory when you are done with the
|
||||
// search
|
||||
void FreeSolutionNodes()
|
||||
{
|
||||
Node *n = m_Start;
|
||||
|
||||
if( m_Start->child )
|
||||
{
|
||||
do
|
||||
{
|
||||
Node *del = n;
|
||||
n = n->child;
|
||||
FreeNode( del );
|
||||
|
||||
del = NULL;
|
||||
|
||||
} while( n != m_Goal );
|
||||
|
||||
FreeNode( n ); // Delete the goal
|
||||
|
||||
}
|
||||
else
|
||||
{
|
||||
// if the start node is the solution we need to just delete the start and goal
|
||||
// nodes
|
||||
FreeNode( m_Start );
|
||||
FreeNode( m_Goal );
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
// Functions for traversing the solution
|
||||
|
||||
// Get start node
|
||||
UserState *GetSolutionStart()
|
||||
{
|
||||
m_CurrentSolutionNode = m_Start;
|
||||
if( m_Start )
|
||||
{
|
||||
return &m_Start->m_UserState;
|
||||
}
|
||||
else
|
||||
{
|
||||
return NULL;
|
||||
}
|
||||
}
|
||||
|
||||
// Get next node
|
||||
UserState *GetSolutionNext()
|
||||
{
|
||||
if( m_CurrentSolutionNode )
|
||||
{
|
||||
if( m_CurrentSolutionNode->child )
|
||||
{
|
||||
|
||||
Node *child = m_CurrentSolutionNode->child;
|
||||
|
||||
m_CurrentSolutionNode = m_CurrentSolutionNode->child;
|
||||
|
||||
return &child->m_UserState;
|
||||
}
|
||||
}
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
// Get end node
|
||||
UserState *GetSolutionEnd()
|
||||
{
|
||||
m_CurrentSolutionNode = m_Goal;
|
||||
if( m_Goal )
|
||||
{
|
||||
return &m_Goal->m_UserState;
|
||||
}
|
||||
else
|
||||
{
|
||||
return NULL;
|
||||
}
|
||||
}
|
||||
|
||||
// Step solution iterator backwards
|
||||
UserState *GetSolutionPrev()
|
||||
{
|
||||
if( m_CurrentSolutionNode )
|
||||
{
|
||||
if( m_CurrentSolutionNode->parent )
|
||||
{
|
||||
|
||||
Node *parent = m_CurrentSolutionNode->parent;
|
||||
|
||||
m_CurrentSolutionNode = m_CurrentSolutionNode->parent;
|
||||
|
||||
return &parent->m_UserState;
|
||||
}
|
||||
}
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
// Get final cost of solution
|
||||
// Returns FLT_MAX if goal is not defined or there is no solution
|
||||
float GetSolutionCost()
|
||||
{
|
||||
if( m_Goal && m_State == SEARCH_STATE_SUCCEEDED )
|
||||
{
|
||||
return m_Goal->g;
|
||||
}
|
||||
else
|
||||
{
|
||||
return FLT_MAX;
|
||||
}
|
||||
}
|
||||
|
||||
// For educational use and debugging it is useful to be able to view
|
||||
// the open and closed list at each step, here are two functions to allow that.
|
||||
|
||||
UserState *GetOpenListStart()
|
||||
{
|
||||
float f,g,h;
|
||||
return GetOpenListStart( f,g,h );
|
||||
}
|
||||
|
||||
UserState *GetOpenListStart( float &f, float &g, float &h )
|
||||
{
|
||||
iterDbgOpen = m_OpenList.begin();
|
||||
if( iterDbgOpen != m_OpenList.end() )
|
||||
{
|
||||
f = (*iterDbgOpen)->f;
|
||||
g = (*iterDbgOpen)->g;
|
||||
h = (*iterDbgOpen)->h;
|
||||
return &(*iterDbgOpen)->m_UserState;
|
||||
}
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
UserState *GetOpenListNext()
|
||||
{
|
||||
float f,g,h;
|
||||
return GetOpenListNext( f,g,h );
|
||||
}
|
||||
|
||||
UserState *GetOpenListNext( float &f, float &g, float &h )
|
||||
{
|
||||
iterDbgOpen++;
|
||||
if( iterDbgOpen != m_OpenList.end() )
|
||||
{
|
||||
f = (*iterDbgOpen)->f;
|
||||
g = (*iterDbgOpen)->g;
|
||||
h = (*iterDbgOpen)->h;
|
||||
return &(*iterDbgOpen)->m_UserState;
|
||||
}
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
UserState *GetClosedListStart()
|
||||
{
|
||||
float f,g,h;
|
||||
return GetClosedListStart( f,g,h );
|
||||
}
|
||||
|
||||
UserState *GetClosedListStart( float &f, float &g, float &h )
|
||||
{
|
||||
iterDbgClosed = m_ClosedList.begin();
|
||||
if( iterDbgClosed != m_ClosedList.end() )
|
||||
{
|
||||
f = (*iterDbgClosed)->f;
|
||||
g = (*iterDbgClosed)->g;
|
||||
h = (*iterDbgClosed)->h;
|
||||
|
||||
return &(*iterDbgClosed)->m_UserState;
|
||||
}
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
UserState *GetClosedListNext()
|
||||
{
|
||||
float f,g,h;
|
||||
return GetClosedListNext( f,g,h );
|
||||
}
|
||||
|
||||
UserState *GetClosedListNext( float &f, float &g, float &h )
|
||||
{
|
||||
iterDbgClosed++;
|
||||
if( iterDbgClosed != m_ClosedList.end() )
|
||||
{
|
||||
f = (*iterDbgClosed)->f;
|
||||
g = (*iterDbgClosed)->g;
|
||||
h = (*iterDbgClosed)->h;
|
||||
|
||||
return &(*iterDbgClosed)->m_UserState;
|
||||
}
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
// Get the number of steps
|
||||
|
||||
int GetStepCount() { return m_Steps; }
|
||||
|
||||
void EnsureMemoryFreed()
|
||||
{
|
||||
#if USE_FSA_MEMORY
|
||||
assert(m_AllocateNodeCount == 0);
|
||||
#endif
|
||||
|
||||
}
|
||||
|
||||
private: // methods
|
||||
|
||||
// This is called when a search fails or is cancelled to free all used
|
||||
// memory
|
||||
void FreeAllNodes()
|
||||
{
|
||||
// iterate open list and delete all nodes
|
||||
typename vector< Node * >::iterator iterOpen = m_OpenList.begin();
|
||||
|
||||
while( iterOpen != m_OpenList.end() )
|
||||
{
|
||||
Node *n = (*iterOpen);
|
||||
FreeNode( n );
|
||||
|
||||
iterOpen ++;
|
||||
}
|
||||
|
||||
m_OpenList.clear();
|
||||
|
||||
// iterate closed list and delete unused nodes
|
||||
typename vector< Node * >::iterator iterClosed;
|
||||
|
||||
for( iterClosed = m_ClosedList.begin(); iterClosed != m_ClosedList.end(); iterClosed ++ )
|
||||
{
|
||||
Node *n = (*iterClosed);
|
||||
FreeNode( n );
|
||||
}
|
||||
|
||||
m_ClosedList.clear();
|
||||
|
||||
// delete the goal
|
||||
|
||||
FreeNode(m_Goal);
|
||||
}
|
||||
|
||||
|
||||
// This call is made by the search class when the search ends. A lot of nodes may be
|
||||
// created that are still present when the search ends. They will be deleted by this
|
||||
// routine once the search ends
|
||||
void FreeUnusedNodes()
|
||||
{
|
||||
// iterate open list and delete unused nodes
|
||||
typename vector< Node * >::iterator iterOpen = m_OpenList.begin();
|
||||
|
||||
while( iterOpen != m_OpenList.end() )
|
||||
{
|
||||
Node *n = (*iterOpen);
|
||||
|
||||
if( !n->child )
|
||||
{
|
||||
FreeNode( n );
|
||||
|
||||
n = NULL;
|
||||
}
|
||||
|
||||
iterOpen ++;
|
||||
}
|
||||
|
||||
m_OpenList.clear();
|
||||
|
||||
// iterate closed list and delete unused nodes
|
||||
typename vector< Node * >::iterator iterClosed;
|
||||
|
||||
for( iterClosed = m_ClosedList.begin(); iterClosed != m_ClosedList.end(); iterClosed ++ )
|
||||
{
|
||||
Node *n = (*iterClosed);
|
||||
|
||||
if( !n->child )
|
||||
{
|
||||
FreeNode( n );
|
||||
n = NULL;
|
||||
|
||||
}
|
||||
}
|
||||
|
||||
m_ClosedList.clear();
|
||||
|
||||
}
|
||||
|
||||
// Node memory management
|
||||
Node *AllocateNode()
|
||||
{
|
||||
|
||||
#if !USE_FSA_MEMORY
|
||||
m_AllocateNodeCount ++;
|
||||
Node *p = new Node;
|
||||
return p;
|
||||
#else
|
||||
Node *address = m_FixedSizeAllocator.alloc();
|
||||
|
||||
if( !address )
|
||||
{
|
||||
return NULL;
|
||||
}
|
||||
m_AllocateNodeCount ++;
|
||||
Node *p = new (address) Node;
|
||||
return p;
|
||||
#endif
|
||||
}
|
||||
|
||||
void FreeNode( Node *node )
|
||||
{
|
||||
|
||||
m_AllocateNodeCount --;
|
||||
|
||||
#if !USE_FSA_MEMORY
|
||||
delete node;
|
||||
#else
|
||||
node->~Node();
|
||||
m_FixedSizeAllocator.free( node );
|
||||
#endif
|
||||
}
|
||||
|
||||
private: // data
|
||||
|
||||
// Heap (simple vector but used as a heap, cf. Steve Rabin's game gems article)
|
||||
vector< Node *> m_OpenList;
|
||||
|
||||
// Closed list is a vector.
|
||||
vector< Node * > m_ClosedList;
|
||||
|
||||
// Successors is a vector filled out by the user each type successors to a node
|
||||
// are generated
|
||||
vector< Node * > m_Successors;
|
||||
|
||||
// State
|
||||
unsigned int m_State;
|
||||
|
||||
// Counts steps
|
||||
int m_Steps;
|
||||
|
||||
// Start and goal state pointers
|
||||
Node *m_Start;
|
||||
Node *m_Goal;
|
||||
|
||||
Node *m_CurrentSolutionNode;
|
||||
|
||||
#if USE_FSA_MEMORY
|
||||
// Memory
|
||||
FixedSizeAllocator<Node> m_FixedSizeAllocator;
|
||||
#endif
|
||||
|
||||
//Debug : need to keep these two iterators around
|
||||
// for the user Dbg functions
|
||||
typename vector< Node * >::iterator iterDbgOpen;
|
||||
typename vector< Node * >::iterator iterDbgClosed;
|
||||
|
||||
// debugging : count memory allocation and free's
|
||||
int m_AllocateNodeCount;
|
||||
|
||||
bool m_CancelRequest;
|
||||
|
||||
};
|
||||
|
||||
template <class T> class AStarState
|
||||
{
|
||||
public:
|
||||
virtual ~AStarState() {}
|
||||
virtual float GoalDistanceEstimate( T &nodeGoal ) = 0; // Heuristic function which computes the estimated cost to the goal node
|
||||
virtual bool IsGoal( T &nodeGoal ) = 0; // Returns true if this node is the goal node
|
||||
virtual bool GetSuccessors( AStarSearch<T> *astarsearch, T *parent_node ) = 0; // Retrieves all successors to this node and adds them via astarsearch.addSuccessor()
|
||||
virtual float GetCost( T &successor ) = 0; // Computes the cost of travelling from this node to the successor node
|
||||
virtual bool IsSameState( T &rhs ) = 0; // Returns true if this node is the same as the rhs node
|
||||
};
|
||||
|
||||
#endif
|
||||
|
||||
|
Loading…
Reference in new issue