Set Matrix Zeroes

setZeroes.java

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

Algorithm:
1. No need extra space and it has O(n*m) complexity in time
2. Go throught the matrix and if it meets 0, then set its row and col to ZERO
3. Once complete, then go throught the matrix again and change ZERO to 0;
*/

public class Solution {
    final int ZERO = 999999;
    public void setZeroes(int[][] matrix) {
        // Start typing your Java solution below
        // DO NOT write main() function
        int row = matrix.length;
        if(row == 0) return;
        int col = matrix[0].length;
        
        for(int i = 0; i < row; i++) {
            for(int j = 0; j < col; j++) {
                if(matrix[i][j] == 0) {
                    setRow(matrix, i, ZERO);
                    setCol(matrix, j, ZERO);
                }
            }
        }
        
        for(int i = 0; i < row; i++) {
            for(int j = 0; j < col; j++) {
                if(matrix[i][j] == ZERO) {
                    matrix[i][j] = 0;
                }
            }
        }
        
        return;
    }
    
    public void setRow(int[][] matrix, int row, int zero) {
        for(int i = 0; i < matrix[0].length; i++) {
            if(matrix[row][i] != 0) matrix[row][i] = zero; 
        }
    }
    
    public void setCol(int[][] matrix, int col, int zero) {
        for(int i = 0; i < matrix.length; i++) {
            if(matrix[i][col] != 0) matrix[i][col] = zero;
        }
    }
}