n皇后问题算法设计python

以下是n皇后问题的算法设计Python实现：

import copy

def solveNQueens(n):
    # 初始化棋盘
    board = [['.' for _ in range(n)] for _ in range(n)]
    res = []

    def backtrack(board, row):
        # 如果已经到达最后一行，说明找到了一组解
        if row == len(board):
            res.append(copy.deepcopy(board))
            return

        # 遍历每一列
        for col in range(len(board)):
            # 判断当前位置是否可以放置皇后
            if isValid(board, row, col):
                # 放置皇后
                board[row][col] = 'Q'
                # 继续搜索下一行
                backtrack(board, row + 1)
                # 回溯，撤销皇后
                board[row][col] = '.'

    def isValid(board, row, col):
        # 检查列是否有皇后冲突
        for i in range(len(board)):
            if board[i][col] == 'Q':
                return False

        # 检查右上方是否有皇后冲突
        i, j = row - 1, col + 1
        while i >= 0 and j < len(board):
            if board[i][j] == 'Q':
                return False
            i, j = i - 1, j + 1

        # 检查左上方是否有皇后冲突
        i, j = row - 1, col - 1
        while i >= 0 and j >= 0:
            if board[i][j] == 'Q':
                return False
            i, j = i - 1, j - 1

        return True

    backtrack(board, 0)
    # 将结果转换为题目要求的格式
    return [[''.join(row) for row in res[i]] for i in range(len(res))]