1161. Maximum Level Sum of a Binary Tree

Difficulty: Medium
34 / 34 test cases passed.
Runtime: 316 ms
Memory Usage: 18 MB

Author: YuriSpiridonov

Medium/1161.MaximumLevelSumofaBinaryTree.py

@@ -0,0 +1,62 @@
+"""
+    Given the root of a binary tree, the level of its root is 1, the level of 
+    its children is 2, and so on.
+    Return the smallest level X such that the sum of all the values of nodes at 
+    level X is maximal.
+
+    Example:
+             1
+            / \
+           7   0
+          / \
+         7  -8
+
+    Input: [1,7,0,7,-8,null,null]
+    Output: 2
+    Explanation: 
+                Level 1 sum = 1.
+                Level 2 sum = 7 + 0 = 7.
+                Level 3 sum = 7 + -8 = -1.
+                So we return the level with the maximum sum which is level 2.
+
+    Note:
+        1. The number of nodes in the given tree is between 1 and 10^4.
+        2. -10^5 <= node.val <= 10^5
+"""
+#Difficulty: Medium
+#34 / 34 test cases passed.
+#Runtime: 316 ms
+#Memory Usage: 18 MB
+
+#Runtime: 316 ms, faster than 89.30% of Python3 online submissions for Maximum Level Sum of a Binary Tree.
+#Memory Usage: 18 MB, less than 69.43% of Python3 online submissions for Maximum Level Sum of a Binary Tree.
+
+# 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 maxLevelSum(self, root: TreeNode) -> int:
+        queue = [root]
+        depth = 0
+        level = 0
+        summ = 0
+        while queue:
+            length = len(queue)
+            level_sum = 0
+            depth += 1
+            while length:
+                length -= 1
+                node = queue.pop(0)
+                level_sum += node.val
+                if node.left:
+                    queue.append(node.left)
+                if node.right:
+                    queue.append(node.right)
+            if level_sum > summ:
+                summ = level_sum
+                level = depth
+        return level