LeetCode_Set Matrix Zeroes

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Set Matrix Zeroes

Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in-place.
（设置矩阵整行&列为0）

Example:



1. 遍历矩阵，集合维护“0”的行列号

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class Solution:
    def setZeroes(self, matrix: 'List[List[int]]') -> 'None':
        """
        Do not return anything, modify matrix in-place instead.
        """
        m, n = len(matrix), len(matrix[0])
        
        columns = set()
        rows = set()
        
        for i in range(m):
            for j in range(n):
                if matrix[i][j] == 0:
                    columns.add(j)
                    rows.add(i)
    
        for i in rows:
            # matrix[i] = [0]*n
            for j in range(n):
                matrix[i][j] = 0
        
        for j in columns:
            for i in range(m):
                matrix[i][j] = 0