Given a non-empty binary search tree and a target value, find the value in the BST that is closest to the target.
Note:
Given target value is a floating point.
You are guaranteed to have only one unique value in the BST that is closest to the target.
Hide Company Tags Microsoft Google Snapchat
Hide Tags Tree Binary Search
Hide Similar Problems (M) Count Complete Tree Nodes (H) Closest Binary Search Tree Value II
BST的题,大部分都是recursion。并且这道题只有一个answer。 难度确实是easy。所以iterative也超级简单。
class Solution {
public:
int closestValue(TreeNode* root, double target) {
int closest = root->val;
if(!root->left && !root->right) return root->val;
while(root){
if(abs(root->val - target) <= abs(closest - target)){
closest = root->val;
}
if(target <= root->val) root = root->left;
else root = root->right;
}
return closest;
}
};
recursion:
class Solution {
public:
int closestValue(TreeNode* root, double target) {
int a = root->val;
TreeNode* node = (target < a) ? root->left : root->right;
if(!node) return a;
int b = closestValue(node, target);
return (abs(a-target) < abs(b-target)) ? a : b;
}
}
};