73. Set Matrix Zeroes

• categories: Code, Interview Question, leetcode, Medium
• source: https://leetcode.com/problems/set-matrix-zeroes
• topics: 2D Array

Given an m x n integer matrix matrix, if an element is 0, set its entire row and column to 0’s.

You must do it in place.

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