From 0a6ac35e9a35ca32f39af1c3db60b3037b347acd Mon Sep 17 00:00:00 2001
From: pjywuv8b9 <3314018306@qq.com>
Date: Sat, 4 Nov 2023 22:13:42 +0800
Subject: [PATCH] =?UTF-8?q?Add=20=E7=AC=AC=E5=9B=9B=E9=A2=98=EF=BC=88guan?=
 =?UTF-8?q?=EF=BC=89?=
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---
 第四题（guan） | 116 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 116 insertions(+)
 create mode 100644 第四题（guan）

diff --git a/第四题（guan） b/第四题（guan）
new file mode 100644
index 0000000..2fea4b9
--- /dev/null
+++ b/第四题（guan）
@@ -0,0 +1,116 @@
+#include <stdio.h>
+int correct(int board[9][9]){//判断是否合法 
+	int col[9]={0},row[9]={0},block[9]={0};
+	int i,j;
+	for(i=0;i<9;++i){
+		for(j=0;j<9;j++){//遍历 
+			int index=1<<(board[i][j]-1);//设置初始位掩码 
+			int blockindex=i/3*3+j/3;//分块 
+			if(board[i][j]!=0){//需要判断的位置 
+				if(row[i]&index){//行合法 
+					printf("False:Invalid initial Sudoku matrix!\n");
+					printf("The number %d in the row %d has been used!",board[i][j],i+1);
+					return 0;
+				}
+				row[i] |=index;//判断一个条件不成立即可 所以位掩码恢复 
+				if(col[j]&index){//列合法 
+					printf("False:Invalid initial Sudoku matrix!\n");
+					printf("The number %d in the rol %d has been used!",board[i][j],j+1);
+					return 0;
+				}
+				col[j] |=index;
+				if(block[blockindex]&index){//块合法 
+					printf("False:Invalid initial Sudoku matrix!\n");
+					printf("The number %d in the block %d has been used!",board[i][j],blockindex+1);
+					return 0;
+				}
+				block[blockindex] |=index;
+			}
+			
+			
+			
+		}
+	}
+	printf("True:Valid initial Sudoku matrix!\n");//以上都通过 成立 
+	return 1;
+	
+}
+int isSafe(int board[9][9],int row,int col,int num){//判断是否合法的函数 
+	int x,i,j;
+	for (x=0;x<=8;x++)//遍历行合法 
+    	if(board[row][x]==num)
+            return 0;
+    for (x=0;x<= 8;x++)//遍历列合法 
+        if(board[x][col]==num)
+            return 0;
+    int sRow=row-row%3,sCol=col-col%3;//初始化块的起始行与列 
+    for(i=0;i<3;i++)
+        for(j=0;j<3;j++)//遍历每个块 
+            if(board[i+sRow][j+sCol]==num)
+                return 0;
+    return 1;
+}
+int solve(int board[9][9]){
+	int num;
+	int i=0,j=0;
+	for(i=0;i<9;i++){
+		for(j=0;j<9;j++){
+			if(board[i][j]==0){//需要填空的部分 
+				for(num=1;num<=9;++num){
+					if(isSafe(board,i,j,num)){//填空中也要满足数独的定义 
+						board[i][j]=num;
+						if(solve(board)){//函数嵌套 
+							return 1;
+						}
+						board[i][j]=0;
+					}
+					
+				}
+				return 0;//遍历后无法填出正确答案 
+			}
+		}
+	}
+	//return 1;
+}
+void print(int board[9][9]){//格式化输出 
+	printf("|---|---|---|---|---|---|\n");
+	int i=0,j=0,s=0,k=0;
+	for(i=0;i<9;++i){
+		for(j=0;j<9;j++){
+			while(j%3==0){
+				printf("| ");
+				break;
+			}
+			printf("%d ",board[i][j]);
+		}
+		printf("|\n");
+		while((i+1)%3==0){
+			printf("|---|---|---|---|---|---|\n");
+			break;
+		}
+	}
+}
+int main(){
+	int board1[9][9]={{5, 3, 0, 0, 7, 0, 0, 0, 0},//初始化矩阵 
+			   {6, 0, 0, 1, 9, 5, 0, 0, 0},
+			   {0, 9, 8, 0, 0, 0, 0, 6, 0},
+			   {8, 0, 0, 0, 6, 0, 0, 0, 3},
+		  	   {4, 0, 0, 8, 0, 3, 0, 0, 1},
+			   {7, 0, 0, 0, 2, 0, 0, 0, 6},
+			   {0, 6, 0, 0, 0, 0, 2, 8, 0},
+			   {0, 0, 0, 4, 1, 9, 0, 0, 5},
+			   {0, 0, 0, 0, 8, 0, 0, 7, 9}};
+	printf("The original Sudoku matrix:\n");
+	print(board1);//格式化输出原矩阵 
+	if(correct(board1)){//判断是否合法 
+		if(solve(board1)){//是否有解 
+			printf("The solution of Sudoku matrix:\n");
+			print(board1);//格式化输出解 
+		}else{
+			printf("No solutions!\n");//无解 
+		}
+		
+	}
+	
+	return 0;
+}
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