Recover Binary Search Tree

Two elements of a binary search tree (BST) are swapped by mistake.

Recover the tree without changing its structure.

#include<iostream>#include<vector>#include<stack>using namespace std;struct TreeNode {int val;TreeNode *left;TreeNode *right;TreeNode(int x) : val(x), left(NULL), right(NULL) {}};void recoverTree(TreeNode *root) {TreeNode* pre_node = NULL;stack<TreeNode*>StackNode;TreeNode*cur_node = root;TreeNode*misnode1 = NULL;TreeNode*misnode2 = NULL;while (1){while (cur_node){StackNode.push(cur_node);cur_node = cur_node->left;}if (StackNode.empty())  break; cur_node = StackNode.top();StackNode.pop();if (pre_node!=NULL&&pre_node->val>cur_node->val){if (!misnode1){misnode1 = pre_node;misnode2 = cur_node;}elsemisnode2 = cur_node;}pre_node = cur_node;cur_node = cur_node->right;}    if (misnode1&&misnode2)swap(misnode1->val,misnode2->val);}