75. Sort Colors

 1 class Solution {
 2     public void sortColors(int[] nums) {
 3         if(nums == null || nums.length == 0) return;
 4         int count0 = 0;
 5         int count1 = 0;
 6         int count2 = 0;
 7         for(int i = 0; i < nums.length; i++) {
 8             if(nums[i] == 0) {
 9                 count0++;
10             }else if(nums[i] == 1) {
11                 count1++;
12             }else {
13                 count2++;
14             }
15         }
16         int i = 0;
17         for(i = 0; i < count0; i++) {
18             nums[i] = 0;
19         }
20         for(i = count0; i < count0 + count1; i++) {
21             nums[i] = 1;
22         }
23         for( ; i < nums.length; i++) {
24             nums[i] = 2;
25         }
26         
27     }
28 }