added two sum IV

david-legend · david-legend · commit 72877549dc3b · 2022-09-09T15:37:40.000Z
diff --git a/leetcode/src/binary_trees/lc_653_two_sum_IV/two_sum.py b/leetcode/src/binary_trees/lc_653_two_sum_IV/two_sum.py
@@ -0,0 +1,25 @@
+
+def two_sum_bst(root, target):
+    def two_sum_helper(node):
+        if node is None:
+            return False
+
+        diff = target - node.val
+        if diff in value_map:
+            return True
+
+        value_map[node.val] = diff
+
+        left = two_sum_helper(node.left)
+        if left:
+            return left
+
+        right = two_sum_helper(node.right)
+        if right:
+            return right
+
+        return False
+
+
+    value_map = {}
+    return two_sum_helper(root)
