leetCode #75 Sort Colors

 1 class Solution {
 2 public:
 3     void sortColors(vector<int>& nums) {
 4         if (nums.size() == 0)
 5         {
 6             return;
 7         }
 8         int count1 = 0, count0 = 0;
 9         for (int num : nums)
10         {
11             if (num == 0)
12             {
13                 ++count0;
14             }
15             if (num == 1)
16             {
17                 ++count1;
18             }
19         }
20         int i = 0;
21         for (; i < count0; ++i)
22         {
23             nums[i] = 0;
24         }
25         for (; i < count0 + count1; ++i)
26         {
27             nums[i] = 1;
28         }
29         for (; i < nums.size(); ++i)
30         {
31             nums[i] = 2;
32         }
33             
34     }
35 };