#include <cstdlib>

#include <iostream>

#include <map>

#include <queue>

#include <sstream>

#include <string>

#include <unordered_map>

#include <unordered_set>

#include <vector>

using namespace std;

class TreeNode {

public:

int val;

TreeNode* left;

TreeNode* right;

TreeNode(int x) { val = x; left = nullptr; right = nullptr;}

};

class Solution {

public:

int closestValue(TreeNode* root, double target) {

int ret = root->val;

while(root != nullptr){

//update ret if the current value is closer to target

ret = abs(target - root->val) < abs(target - ret)

? root->val

: ret;

//binary search

root = root->val > target

? root->left

: root->right;

}

return ret;

}

};

int main() {

Solution sol;

TreeNode e(2);

e.left = new TreeNode(1);

e.right = new TreeNode(4);

cout << sol.closestValue(&e, 1.7) << endl;

return 0;

}