# -*- coding: utf-8 -*-
# Time : 2023/11/3 17:21
# Author : lirunsheng
# User : l'r's
# Software: PyCharm
# File : demo6.py

import sys
import itertools

import numpy as np


def tsp_dp(distances):
    n = len(distances)
    dp = [[sys.maxsize] * n for _ in range(1 << n)]
    dp[1][0] = 0

    for mask in range(1, 1 << n):
        for current in range(n):
            if mask & (1 << current):
                for previous in range(n):
                    if previous != current and mask & (1 << previous):
                        dp[mask][current] = min(dp[mask][current], dp[mask ^ (1 << current)][previous] + distances[previous][current])

    shortest_path = sys.maxsize
    end_mask = (1 << n) - 1
    last_city = -1

    for i in range(1, n):
        if shortest_path > dp[end_mask][i] + distances[i][0]:
            shortest_path = dp[end_mask][i] + distances[i][0]
            last_city = i

    path = []
    mask = end_mask
    while last_city >= 0:
        path.append(last_city)
        new_mask = mask ^ (1 << last_city)
        last_city = -1
        for i in range(n):
            if new_mask & (1 << i):
                if last_city == -1 or dp[mask][last_city] + distances[last_city][i] == dp[mask][i]:
                    last_city = i
        mask = new_mask

    path.append(0)
    path.reverse()

    return shortest_path, path
#
# # 测试代码
# distances = [
#     [0, 2, 9, 10],
#     [1, 0, 6, 4],
#     [15, 7, 0, 8],
#     [6, 3, 12, 0]
# ]



# 测试代码
distances = np.array([
    [np.inf, 80, 99, np.inf, 64, np.inf],
    [80, np.inf, 12, 45, 74, 13],
    [99, 12, np.inf, 25, np.inf, 61],
    [np.inf, 45, 25, np.inf, 45, 47],
    [64, 74, np.inf, 45, np.inf, np.inf],
    [np.inf, 13, 61, 47, np.inf, np.inf]
])

shortest_path, path = tsp_dp(distances)
print("最短路径长度为:", shortest_path)
print("最短路径为:", path)