愛比的新手筆記

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:Taiwan is a country. 臺灣是我的國家

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

public class Solution {
    public TreeNode SearchBST(TreeNode root, int val) {
            if (root == null) return null;
            if (root.val == val) return root;
            return SearchBST(root.left, val) ?? SearchBST(root.right, val);        
    }
}

Taiwan is a country. 臺灣是我的國家