题解 | #Sudoku#

# 菜鸡参考大神代码写的，马一下
import sys

sudoku = []

nums = set(range(1, 10))

for line in sys.stdin:
    sudoku.append(list(map(int, line.strip().split())))

def sub_matrix(p):
    """calculate the start location of a 3X3 matrix which contain p"""
    x, y = p
    boder = [0, 3, 6]
    if x not in boder:
        if 0 <= x <= 2:
            x = 0
        elif 3 <= x <= 5:
            x = 3
        else:
            x = 6
    if y not in boder:
        if 0 <= y <= 2:
            y = 0
        elif 3 <= y <= 5:
            y = 3
        else:
            y = 6
    return [x, y]

def check_sudoku_properties(sudoku, i, j, num):
    line_x, line_y, start, matrix = sudoku[i], [], sub_matrix([i, j]), []
    for line in sudoku:
        line_y.append(line[j])
    m, n = start
    for line in sudoku[m:m+3]:
        matrix.extend(line[n:n+3])
    if num in line_x or num in line_y or num in matrix:
        return False
    else:
        return True

def dfs(sudoku):
    for i in range(9):
        for j in range(9):
            if sudoku[i][j] == 0:
                for num in nums:
                    # print(num, i, j)
                    check = check_sudoku_properties(sudoku, i, j, num)
                    # print(check)
                    if check:
                        sudoku[i][j] = num
                        # print(num, i, j)
                        res = dfs(sudoku)
                        if res:
                            return True
                        sudoku[i][j] = 0
                return False
    return True

dfs(sudoku)

for line in sudoku:
    print(*line, sep=' ')