Time: 289 ms (100.00%), Space: 50.8 MB (51.67%) - LeetHub

Author: hogan-tech

1973-count-nodes-equal-to-sum-of-descendants/1973-count-nodes-equal-to-sum-of-descendants.py

@@ -0,0 +1,36 @@
+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 equalToDescendants(self, root: Optional[TreeNode]) -> int:
+        count = 0
+
+        def countNodes(node: Optional[TreeNode]) -> int:
+            nonlocal count
+            if node == None:
+                return 0
+            left = countNodes(node.left)
+            right = countNodes(node.right)
+            if left + right == node.val:
+                count += 1
+            return node.val + left + right
+        
+        countNodes(root)
+        return count
+
+
+root = TreeNode(10)
+root.left = TreeNode(3)
+root.left.left = TreeNode(2)
+root.left.right = TreeNode(1)
+root.right = TreeNode(4)
+
+print(Solution().equalToDescendants(root))