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 };
