矩阵置0

题目：矩阵置0

link:https://leetcode.cn/problems/set-matrix-zeroes/description/?envType=study-plan-v2&envId=top-interview-150

class Solution:
    def setZeroes(self, matrix: List[List[int]]) -> None:
        """
        Do not return anything, modify matrix in-place instead.
        """
        m = len(matrix)
        n = len(matrix[0])

        rows = [0] * m
        columns = [0] * n

        for i in range(m):
            for j in range(n):
                if(matrix[i][j]==0):
                    rows[i] = 1
                    columns[j] = 1
        print(rows,columns)
        for i in range(m):
            for j in range(n):
                if(rows[i] or columns[j]):
                    matrix[i][j] = 0
      

        

        ```

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