LeetCode 700. Search in a Binary Search Tree

考点	难度
Tree	Easy

题目

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.

思路

利用left child小于parent，right child大于parent的性质找到和val相等的parent。

答案

class Solution {
    public TreeNode searchBST(TreeNode root, int val) {
		while (root != null)
		{
			if ( val < root.val ) root = root.left;
			else if ( val > root.val ) root = root.right;
			else return root;
		}
		return root;
	}
}