[Leetcode] Recover Binary Search Tree

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
private:
    vector<int> val;
    vector<TreeNode*> seq;

public:
    void recoverTree(TreeNode *root) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        val.clear();
        seq.clear();
        inorderTraverse(root);
        
        sort(val.begin(), val.end());
        for (int i = 0; i < seq.size(); ++i)
        {
            seq[i]->val = val[i];
        }
    }
    
    void inorderTraverse(TreeNode* root)
    {
        if (!root)
            return;
        
        inorderTraverse(root->left);
        val.push_back(root->val);
        seq.push_back(root);
        inorderTraverse(root->right);        
    }
};