Set Matrix Zeroes Cont…

Question: Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in-place.

Example 1:

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

You may view the full question here.

Approach 3: After some digging, found a brilliant article. After a few iterations, this is what we have —

//Approach 3:
//Runtime: 1ms
//Memory usage: 44.8MB
class Solution {
    public void setZeroes(int[][] matrix) {
        //Check if First Column should be set to Zero
        boolean setColZero = false;
        for(int r = 0; r<matrix.length; r++){
            if(matrix[r][0] == 0){
                setColZero = true;
                break;
            }
        }
        
        //Check if First Row should be set to Zero
        boolean setRowZero = false;
        for(int c = 0; c<matrix[0].length; c++){
            if(matrix[0][c] == 0){
                setRowZero = true;
                break;
            }
        }
        
        //Check
        for(int r = 1; r<matrix.length; r++){
            for(int c = 1; c<matrix[0].length; c++){
                if(matrix[r][c]==0){
                    matrix[r][0] = 0;
                    matrix[0][c] = 0;
                }
            }
        }
        
        //Set zeroes
        for(int r = 1; r<matrix.length; r++){
            for(int c = 1; c<matrix[0].length; c++){
                if(matrix[r][0]==0 || matrix[0][c]==0){
                    matrix[r][c] = 0;
                }
            }
        }
        
        //Set First column zero
        if(setColZero){
            for(int r = 0; r<matrix.length; r++){
                matrix[r][0] = 0;
            }
        }
        //set First row zero
        if(setRowZero){
            for(int c = 0; c<matrix[0].length; c++){
                matrix[0][c] = 0;
            }
        }
    }
}

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Cheers & Chao!