Set Matrix Zeroes

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

click to show follow up.

Follow up:

Did you use extra space?
A straight forward 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?

 

 public class Solution {
     public void setZeroes(int[][] matrix) {
         if(matrix == null || matrix.length == 0 || matrix[0].length == 0) return;
         int row = 0, col = 0;
         boolean sig = true;
         for(int i = 0; i < matrix.length; i ++){
             for(int j = 0; j < matrix[0].length; j ++){
                 if(matrix[i][j] == 0){
                     if(sig){
                         row = i;
                         col = j;
                         sig = false;
                     } else {
                         matrix[row][j] = 0;
                         matrix[i][col] = 0;
                     }
                 }
             }
         }
         if(sig) return;
         for(int i = 0; i < matrix.length; i ++){
             for(int j = 0; j < matrix[0].length; j ++){
                 if((matrix[row][j] == 0 || matrix[i][col] == 0) && i != row && j != col) matrix[i][j] = 0;
             }
         }
         for(int i = 0; i < matrix.length; i ++){
             matrix[i][col] = 0;
         }
         for(int j = 0; j < matrix[0].length; j ++){
             matrix[row][j] = 0;
         }
     }
 }