653两数之和IV

二叉搜索树中的两数之和，通过遍历得到一个vector数组，转化出1两数之和问题。

#include
#include
#include
#include
using namespace std;
struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode() : val(0), left(nullptr), right(nullptr) {}
    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
    TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
};
class Solution {
public:
    void inorder(TreeNode* root, vector& res) {
        if (root == nullptr) {
            return;
        }
        inorder(root->left, res);
        res.push_back(root->val);
        inorder(root->right, res);
    }
    bool findTarget(TreeNode* root, int k) {
        vectora;
        inorder(root, a);
        unordered_setset;
        for (int i = 0; i < a.size(); i++) {
            auto it = set.find(k - a[i]);
            if (it != set.end())return true;
            set.insert(a[i]);
        }
        return false;
    }
};
void print(TreeNode* a) {
    if (a != nullptr) {
        cout << a->val;
        print(a->left);
        print(a->right);
    }
}

int main() {
    Solution test;
    TreeNode* c = new TreeNode(1);
    TreeNode* b = new TreeNode(3);
    TreeNode* a = new TreeNode(2,c, b);
    cout << test.findTarget(a, 3);
}