【leetcode刷题笔记】Set Matrix Zeroes

 1 public class Solution {
 2     public void setZeroes(int[][] matrix) {
 3         int m = matrix.length;
 4         int n = matrix[0].length;
 5         boolean first_column_zero = false;
 6         boolean first_row_zero = false;
 7         
 8         for(int i = 0;i < m;i ++){
 9             if(matrix[i][0] == 0)
10                 first_column_zero =true;
11         }
12         for(int i = 0;i < n;i ++){
13             if(matrix[0][i] == 0)
14                 first_row_zero = true;
15         }
16         
17         for(int i = 1;i < m;i++){
18             for(int j = 1;j < n;j ++){
19                 if(matrix[i][j]== 0){
20                     matrix[i][0] = 0;
21                     matrix[0][j]= 0; 
22                 }
23             }
24         }
25         
26         for(int i = 1;i < m;i++){
27             for(int j = 1;j < n;j ++){
28                 if(matrix[i][0] == 0 || matrix[0][j]== 0 )
29                     matrix[i][j]= 0; 
30             }
31         }
32         
33         if(first_column_zero){
34             for(int i = 0;i < m;i ++)
35                 matrix[i][0] = 0;
36         }
37         if(first_row_zero){
38             for(int i = 0;i < n;i ++)
39                 matrix[0][i] = 0;
40         }
41     }
42 }