leetcode-700-easy

Search in a Binary Search 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 <= 107
root is a binary search tree.
1 <= val <= 107

思路一：递归查找

    public TreeNode searchBST(TreeNode root, int val) {
        if (root == null) {
            return null;
        }

        if (root.val == val) {
            return root;
        } else if (root.val > val) {
            return searchBST(root.left, val);
        } else {
            return searchBST(root.right, val);
        }
    }