700. Search in a Binary Search Tree

Problem

Tags: Tree, Binary Search Tree, Binary Tree

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 <= 10^7
• root is a binary search tree.
• 1 <= val <= 10^7

Code

JS

// 700. Search in a Binary Search Tree (2/21/53745)
// Runtime: 92 ms (36.63%) Memory: 45.66 MB (93.98%) 

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} root
 * @param {number} val
 * @return {TreeNode}
 */
function searchBST(root, val) {
    if (!root) return null;
    if (root.val === val) return root;
    if (root.val > val) return searchBST(root.left, val);
    else return searchBST(root.right, val);
}