700

700. Search in a Binary Search Tree (Easy)

You are given the root of a binary search tree (BST) and an integer val.

Find the node in the BST that the node's value equals val and return the subtree rooted with that node. If such a node does not exist, return null.

 

Example 1:

Input: root = [4,2,7,1,3], val = 2
Output: [2,1,3]

Example 2:

Input: root = [4,2,7,1,3], val = 5
Output: []

 

Constraints:

• The number of nodes in the tree is in the range [1, 5000].
• 1 <= Node.val <= 107
• root is a binary search tree.
• 1 <= val <= 107

Companies:
Microsoft, Amazon

Related Topics:
Tree, Binary Search Tree, Binary Tree

Similar Questions:

• Closest Binary Search Tree Value (Easy)
• Insert into a Binary Search Tree (Medium)

Solution 1.

// OJ: https://leetcode.com/problems/search-in-a-binary-search-tree/
// Author: github.com/lzl124631x
// Time: O(H)
// Space: O(H)
class Solution {
public:
    TreeNode* searchBST(TreeNode* root, int val) {
        if (!root) return nullptr;
        if (root->val == val) return root;
        return val > root->val ? searchBST(root->right, val) : searchBST(root->left, val);
    }
};