python写个数独破解器，代码实例

好的，以下是一个简单的数独破解器的Python代码实例：

def solve_sudoku(board):
    """
    Solve a Sudoku board using a backtracking algorithm.

    :param board: 9x9 2D list of integers representing the Sudoku board
    :return: True if the board is solvable, False otherwise
    """
    # Find the next empty cell
    row, col = find_empty_cell(board)

    # Base case: if there are no empty cells, the board is solved
    if row is None:
        return True

    # Try each number from 1 to 9 in the empty cell
    for num in range(1, 10):
        # Check if the number is valid in the given row, column, and box
        if is_valid(board, row, col, num):
            # If the number is valid, set it on the board
            board[row][col] = num
            # Recursively try to solve the board with the modified cell
            if solve_sudoku(board):
                return True
            # If the modified cell leads to an unsolvable board, backtrack
            board[row][col] = 0

    # If none of the numbers from 1 to 9 are valid for the empty cell, backtrack
    return False


def find_empty_cell(board):
    """
    Find the next empty cell on the board.

    :param board: 9x9 2D list of integers representing the Sudoku board
    :return: (row, col) tuple of the next empty cell, or (None, None) if the board is full
    """
    for row in range(9):
        for col in range(9):
            if board[row][col] == 0:
                return (row, col)
    return (None, None)


def is_valid(board, row, col, num):
    """
    Check whether the given number is valid in the given row, column, and box.

    :param board: 9x9 2D list of integers representing the Sudoku board
    :param row: row index of the cell being checked
    :param col: column index of the cell being checked
    :param num: the number being checked for validity
    :return: True if the number is valid, False otherwise
    """
    # Check row
    if num in board[row]:
        return False

    # Check column
    if num in [board[i][col] for i in range(9)]:
        return False

    # Check box
    box_row, box_col = 3 * (row // 3), 3 * (col // 3)
    if num in [board[r][c] for r in range(box_row, box_row + 3) for c in range(box_col, box_col + 3)]:
        return False

    return True

你可以调用该函数并传入一个9x9的矩阵表示数独问题。该函数将返回True如果数独问题有解，否则返回False。如果问题有解，解将被直接修改在传入的矩阵中。