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);
}
}