> For the complete documentation index, see [llms.txt](https://jenhsuan.gitbook.io/algorithm/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jenhsuan.gitbook.io/algorithm/leetcode/653.-two-sum-iv-input-is-a-bst.md).

# 653. Two Sum IV - Input is a BST

## 1.問題

* 判斷樹中任意兩束的總和是否等於k

![](/files/-LKMdCVSHhaA3K91ieBI)

## 2.想法

## 3.程式碼

```
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    bool findTarget(TreeNode* root, int k) {
        vector<int> v;
        getList(root, v);
        for (int i = 0; i < v.size(); i++) {
            for (int j = i + 1; j < v.size(); j++) {
                if (v[i] + v[j] == k) {
                    return true;
                }
            }    
        }
        return false;
    }
private:
    void getList(TreeNode* root, vector<int>& v) {
        if (root) {
            if (root->left){
                getList(root->left, v);
            }
            v.push_back(root->val);
            if (root->right){
                getList(root->right, v);
            }
        }
    }
};
```

## 4.Performance

![](/files/-LKMdO3p0jT9jFqijxQL)