LeetCode: Sort Colors

没写出来，看到网上一个非常好的code，不过这个code不太容易想出来

 1 class Solution {
 2 public:
 3     void sortColors(int A[], int n) {
 4         // Start typing your C/C++ solution below
 5         // DO NOT write int main() function
 6         int pos[3] = {};
 7         for (int i = 0; i < n; i++) {
 8             int cur = A[i];
 9             for (int j = 2; j >= cur; j--) {
10                 A[pos[j]] = j;
11                 pos[j]++;
12             }
13         }
14     }
15 };

下面是一个比较容易想出来的code。

 1 class Solution {
 2 public:
 3     void sortColors(int A[], int n) {
 4         // Start typing your C/C++ solution below
 5         // DO NOT write int main() function
 6         int left = 0;
 7         int right = n-1;
 8         int mid = n-1;
 9         while (left <= mid) {
10             if (A[left] == 2) {
11                 int tmp = A[right];
12                 A[right] = A[left];
13                 A[left] = tmp;
14                 right--;
15                 if (right < mid) mid = right;
16             }
17             if (A[left] == 1) {
18                 int tmp = A[mid];
19                 A[mid] = A[left];
20                 A[left] = tmp;
21                 mid--;
22             }
23             if (A[left] == 0) left++;
24         }
25     }
26 };

 1 public class Solution {
 2     public void SortColors(int[] nums) {
 3         int left = 0, right = nums.Length - 1, mid = nums.Length - 1;
 4         while (left <= mid) {
 5             if (nums[left] == 2) {
 6                 int tmp = nums[right];
 7                 nums[right] = nums[left];
 8                 nums[left] = tmp;
 9                 right--;
10                 if (right < mid) mid = right;
11             }
12             if (nums[left] == 1) {
13                 int tmp = nums[mid];
14                 nums[mid] = nums[left];
15                 nums[left] = tmp;
16                 mid--;
17             }
18             if (nums[left] == 0) left++;
19         }
20     }
21 }

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posted @ 2013-04-21 06:21 ying_vincent 阅读(129) 评论(0) 收藏举报

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