八皇后用python写

八皇后问题是一个经典的回溯算法问题，下面是用 Python 实现的代码：

def printBoard(board):
    for i in range(len(board)):
        for j in range(len(board)):
            print(board[i][j], end=' ')
        print()

def isSafe(board, row, col):
    for i in range(col):
        if board[row][i] == 1:
            return False

    for i,j in zip(range(row,-1,-1), range(col,-1,-1)):
        if board[i][j] == 1:
            return False

    for i,j in zip(range(row,len(board),1), range(col,-1,-1)):
        if board[i][j] == 1:
            return False

    return True

def solveNQueens(board, col):
    if col >= len(board):
        return True

    for i in range(len(board)):
        if isSafe(board, i, col):
            board[i][col] = 1

            if solveNQueens(board, col+1):
                return True

            board[i][col] = 0

    return False

def solve(n):
    board = [[0 for x in range(n)] for y in range(n)]

    if solveNQueens(board, 0) == False:
        print("No solution found")
        return False

    printBoard(board)
    return True

n = 8
solve(n)

该代码定义了三个函数：

- `printBoard()` 用于打印棋盘；
- `isSafe()` 判断当前位置是否可放置皇后；
- `solveNQueens()` 用于递归求解八皇后问题。

最后，调用 `solve()` 函数即可求解八皇后问题。