D. J.:

- Added the leetcode problem and solution for 637 Average of Levels in Binary Tree

Author: nobodyPerfecZ

README.md

@@ -73,6 +73,7 @@ This repository contains awesome LeetCode problems and solutions written in Pyth
 - [383 Ransom Note](https://leetcode.com/problems/ransom-note/description/)
 - [392 Is Subsequence](https://leetcode.com/problems/is-subsequence/description/)
 - [452 Minimum Number of Arrows to Burst Balloons](https://leetcode.com/problems/minimum-number-of-arrows-to-burst-balloons/description/)
+- [637 Average of Levels in Binary Tree](https://leetcode.com/problems/average-of-levels-in-binary-tree/description/)
 
 ## Development 🔧
 

awesome_python_leetcode/_637_average_of_levels_in_binary_tree.py

@@ -0,0 +1,30 @@
+from typing import List, Optional
+
+from awesome_python_leetcode.tree import TreeNode
+
+
+class Solution:
+    def averageOfLevels(self, root: Optional[TreeNode]) -> List[float]:
+        """
+        Given the root of a binary tree, return the average value of the nodes on each
+        level in the form of an array. Answers within 10-5 of the actual answer will be
+        accepted.
+        """
+        parents = [root]
+        result = []
+        while parents:
+            # Build average value
+            total_sum = 0
+            for p in parents:
+                total_sum += p.val
+            result.append(total_sum / len(parents))
+
+            # Build childs
+            childs = []
+            for p in parents:
+                if p.left:
+                    childs.append(p.left)
+                if p.right:
+                    childs.append(p.right)
+            parents = childs
+        return result

tests/test_637_average_of_levels_in_binary_tree.py

@@ -0,0 +1,19 @@
+from typing import List
+
+import pytest
+
+from awesome_python_leetcode._637_average_of_levels_in_binary_tree import Solution
+from awesome_python_leetcode.tree import TreeNode
+
+
+@pytest.mark.parametrize(
+    argnames=["root", "expected"],
+    argvalues=[
+        ([3, 9, 20, None, None, 15, 7], [3.00000, 14.50000, 11.00000]),
+        ([3, 9, 20, 15, 7], [3.00000, 14.50000, 11.00000]),
+    ],
+)
+def test_func(root: List[int], expected: List[float]):
+    root = TreeNode.build(root)
+    average_of_levels = Solution().averageOfLevels(root)
+    assert average_of_levels == expected