LeetCode OJ-- Recover Binary Search Tree ***@

https://oj.leetcode.com/problems/recover-binary-search-tree/

一棵二叉搜索树，二叉搜索树的特征是，中根遍历的话，得到的序列是递增的

题目中，有两个节点弄混了，让恢复这个二叉搜索树 

class Solution {
public:
    TreeNode *LastNode = new TreeNode(INT_MIN);
    
    void recoverTree(TreeNode *root) {
        if(root == NULL)
            return;
        
        TreeNode **n1 = (TreeNode**)malloc(sizeof(TreeNode*));
        TreeNode **n2 = (TreeNode**)malloc(sizeof(TreeNode*));
	*n1 = NULL;
	*n2 = NULL;
        find(root,n1,n2);
        //swap
        int temp;
	temp = (*n1)->val; (*n1)->val = (*n2)->val; (*n2)->val = temp;
    }
    
    //中根遍历
    void find(TreeNode *root, TreeNode **n1, TreeNode **n2) 
    {
        if(root == NULL)
            return;
            
        find(root->left,n1,n2);
        
        //分别处理了是 2 1 还是，3 2 1 的情况，高！
        if(*n1 == NULL && root->val < LastNode->val)
        {
            *n1 = LastNode;
        }
        if(*n1 != NULL && root->val < LastNode->val)
        {
            *n2 = root;
        }
        
        LastNode = root;
        
        find(root->right,n1,n2);
    }
};