Medium
Given an m x n matrix, if an element is 0 set its entire row and column to 0. LeetCode mutates in place; here return the modified matrix.
Input: grid = [[1,1,1],[1,0,1],[1,1,1]] Output: [[1,0,1],[0,0,0],[1,0,1]]
Input: grid = [[0,1],[1,1]] Output: [[0,0],[0,1]]