73. Set Matrix Zeroes (Leetcode || Java || Medium)

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.

Example 1:

Input: matrix = [[1,1,1],[1,0,1],[1,1,1]]
Output: [[1,0,1],[0,0,0],[1,0,1]]

Example 2:

Input: matrix = [[0,1,2,0],[3,4,5,2],[1,3,1,5]]
Output: [[0,0,0,0],[0,4,5,0],[0,3,1,0]]

Constraints:

• m == matrix.length
• n == matrix[0].length
• 1 <= m, n <= 200
• -231 <= matrix[i][j] <= 231 - 1

Follow up:

• A straightforward solution using O(mn) space is probably a bad idea.
• A simple improvement uses O(m + n) space, but still not the best solution.
• Could you devise a constant space solution?

SOLUTION

class Solution {
public void setZeroes(int[][] matrix) {
int m = matrix.length;
int n = matrix[0].length;

int[][] temp = new int[m][n];//Declaring a new matrix

for(int i = 0; i < m; i++){
for(int j = 0; j < n; j++){
temp[i][j] = matrix[i][j];//Assingning values of given matrix into temporary mar
}
}


for(int i = 0; i < m; i++){
for(int j = 0; j < n; j++){
if(matrix[i][j] == 0){//if value is 0 in the original matrix the converting the temp matrix elements to 0

for(int r = 0; r < m; r++){
temp[r][j] = 0;//converting column elements to 0
}
for(int c = 0; c < n; c++){
temp[i][c] = 0;//converting row elements to 0
}
}
}
}

for(int row = 0; row < m; row++){//Assigning elemenats of temp to
for(int col = 0; col < n; col++){
matrix[row][col] = temp[row][col];
}
}
}
}