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leetcode - Recover Binary Search Tree

2013-12-15 21:02  张汉生  阅读(188)  评论(0)    收藏  举报

 

 1 //比较巧妙的解决方法，copied from：
 2 //http://blog.csdn.net/jellyyin/article/details/9018803
 3 class Solution {
 4 public:
 5     void recoverTree(TreeNode *root) {
 6         // Start typing your C/C++ solution below
 7         // DO NOT write int main() function
 8         TreeNode *n1=NULL;
 9         TreeNode *n2=NULL;
10         TreeNode *prev=NULL;
11         findTwoNodes(root,n1,n2,prev);
12         
13         if(n1!=NULL && n2!=NULL)
14         {
15             int tmp=n2->val;
16             n2->val=n1->val;
17             n1->val=tmp;
18         }
19     }
20     void findTwoNodes(TreeNode *root, TreeNode *&n1, TreeNode *&n2, TreeNode *&prev)
21     {
22         if(root==NULL) return;
23         
24         findTwoNodes(root->left,n1,n2,prev);
25         if(prev!=NULL && prev->val > root->val)
26         {
27             n2=root;
28             if(n1==NULL)
29             {
30                 n1=prev;
31             }
32         }
33         prev=root;
34         findTwoNodes(root->right,n1,n2,prev);
35     }
36 };