700. Search in a Binary Search Tree

Author: papilo-cloud

Trees/searchBST.py

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+# 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
+
+
+from typing import Optional
+
+# Definition for a binary tree node.
+class TreeNode:
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+class Solution:
+    def searchBST(self, root: Optional[TreeNode], val: int) -> Optional[TreeNode]:
+        if not root:
+            return None
+        if root.val == val:
+            return root
+        if root.val < val:
+            return self.searchBST(root.right, val)
+        else:
+            return self.searchBST(root.left, val)