[20220902] 9월 2일 문제 풀이

Author: iamminji

challenge/2022/09/02-average-of-levels-in-binary-tree.py

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+# https://leetcode.com/problems/average-of-levels-in-binary-tree/
+# 637. Average of Levels in Binary Tree
+
+from typing import Optional, List
+from common.leetcodeds import TreeNode
+from collections import deque, defaultdict
+
+
+class Solution:
+    def averageOfLevels(self, root: Optional[TreeNode]) -> List[float]:
+        queue = deque()
+        queue.append((0, root))
+        result = []
+        count = defaultdict(int)
+
+        while queue:
+            depth, node = queue.popleft()
+            if depth >= len(result):
+                result.append(node.val)
+            else:
+                result[depth] += node.val
+
+            count[depth] += 1
+
+            if node.left is not None:
+                queue.append((depth + 1, node.left))
+            if node.right is not None:
+                queue.append((depth + 1, node.right))
+
+        for idx in range(len(result)):
+            result[idx] /= count[idx]
+
+        return result