73-矩阵置零

class Solution:
    def setZeroes(self, matrix: List[List[int]]) -> None:
        """
        Do not return anything, modify matrix in-place instead.
        """
        row0_flag = False
        col0_flag = False
        for i in range(len(matrix)):
            if matrix[i][0] == 0:
                col0_flag = True
                break
        for i in range(len(matrix[0])):
            if matrix[0][i] == 0:
                row0_flag = True
                break
        for i in range(1, len(matrix)):
            for j in range(1, len(matrix[0])):
                if matrix[i][j] == 0:
                    matrix[i][0] = matrix[0][j] = 0

        for i in range(1, len(matrix)):
            for j in range(1, len(matrix[0])):
                if matrix[i][0] == 0 or matrix[0][j] == 0:
                    matrix[i][j] = 0
        if row0_flag == True:
            for i in range(len(matrix[0])):
                matrix[0][i] = 0
        if col0_flag == True:
            for i in range(len(matrix)):
                matrix[i][0] = 0