BST - easy - check if bst has two nodes sum equal to target

Author: rajithst

binary_search_tree/easy/two_sum_iv.py

@@ -0,0 +1,35 @@
+# Definition for a binary tree node.
+from typing import Optional
+
+
+class TreeNode:
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+
+
+class Solution:
+    def findTarget(self, root: Optional[TreeNode], k: int) -> bool:
+
+        result = []
+
+        def dfs(node):
+            if node:
+                dfs(node.left)
+                result.append(node.val)
+                dfs(node.right)
+
+        dfs(root)
+
+        p1 = 0
+        p2 = len(result) - 1
+        while p1 < p2:
+            s = result[p1] + result[p2]
+            if s == k:
+                return True
+            elif s < k:
+                p1 += 1
+            else:
+                p2 -= 1
+        return False