用python解决拉斯维加斯算法求n皇后问题

拉斯维加斯算法是一种随机化算法，可以用于求解n皇后问题。下面是用Python实现的代码：

import random

def conflict(state, nextX):
    nextY = len(state)
    for i in range(nextY):
        if abs(state[i] - nextX) in (0, nextY - i):
            return True
    return False

def queens(num=8, state=()):
    for pos in range(num):
        if not conflict(state, pos):
            if len(state) == num - 1:
                return (pos,)
            else:
                solution = queens(num, state + (pos,))
                if solution is not None:
                    return (pos,) + solution
    return None

def las_vegas_queens(num=8):
    while True:
        board = list(range(num))
        random.shuffle(board)
        solution = queens(num, tuple(board))
        if solution is not None:
            return solution

print(las_vegas_queens(8))

这段代码中，`conflict`函数用于检查当前位置和之前位置是否有冲突，`queens`函数用于递归求解n皇后问题，`las_vegas_queens`函数则是用拉斯维加斯算法来解决n皇后问题。