Leetcode 700 - Search in a binary search tree

Note:

  • Use dfs
  • Know BST’s left subtree vals are smaller than root node val.

Question:

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:

img

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

Code:

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/**
* 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}
*/
var searchBST = function(root, val) {
if (!root) return null;
if (root.val === val) return root;
if (root.val > val) return searchBST(root.left, val);
return searchBST(root.right, val);
};