/**
knakul853
 */
class Solution {
public:
    bool findTarget(TreeNode* root, int k) {

        map<int,int>mp;
        vector<int>ans;
       dfs(root, ans);
        int n = ans.size();
        for(int i=0;i<n;i++)
        {
            if(mp.count(k-ans[i]))return true;
            mp[ans[i]] = 1;
        }
        return false;
    }

    void dfs(TreeNode* root, vector<int>&ans)
    {
        if(!root){
            return;
        }
        ans.push_back(root->val);

        dfs(root->left, ans);
        dfs(root->right, ans);

    }
};