题目：

题解：

class Solution:
    def setZeroes(self, matrix: List[List[int]]) -> None:
        m, n = len(matrix), len(matrix[0])
        flag_col0 = False
        
        for i in range(m):
            if matrix[i][0] == 0:
                flag_col0 = True
            for j in range(1, n):
                if matrix[i][j] == 0:
                    matrix[i][0] = matrix[0][j] = 0
        
        for i in range(m - 1, -1, -1):
            for j in range(1, n):
                if matrix[i][0] == 0 or matrix[0][j] == 0:
                    matrix[i][j] = 0
            if flag_col0:
                matrix[i][0] = 0