solves average of levels in binary tree

Author: anishLearnsToCode

Diff for: README.md

@@ -165,12 +165,18 @@
 | 624 | 🔒 [Maximum Distance in Arrays](https://leetcode.com/problems/maximum-distance-in-arrays) | |
 | 628 | [Maximum Product of Three Numbers](https://leetcode.com/problems/maximum-product-of-three-numbers) | [![Java](assets/java.png)](src/MaximumProductOfThreeNumbers.java) [![Python](assets/python.png)](python/maximum_product_of_three_numbers.py) |
 | 633 | [Sum Square Numbers](https://leetcode.com/problems/sum-of-square-numbers) | [![Java](assets/java.png)](src/SumOfSquareNumbers.java) [![Python](assets/python.png)](python/sum_of_squares_numbers.py) |
-| 637 | [Average of Levels in Binary Tree](https://leetcode.com/problems/average-of-levels-in-binary-tree) | |
+| 637 | [Average of Levels in Binary Tree](https://leetcode.com/problems/average-of-levels-in-binary-tree) | [![Java](assets/java.png)](src/AverageLevelsOfBinaryTree.java) [![Python](assets/python.png)](python/)
 | 643 | [Maximum Average SubArray I](https://leetcode.com/problems/maximum-average-subarray-i) | [![Java](assets/java.png)](src/MaximumAverageSubArrayI.java) [![Python](assets/python.png)](python/maximum_average_subarray_I.py) |
 | 645 | [Set Mismatch](https://leetcode.com/problems/set-mismatch) | [![Java](assets/java.png)](src/SetMismatch.java) [![Python](assets/python.png)](python/set_mismatch.py) |
 | 653 | [Two Sum IV - Input is a BST](https://leetcode.com/problems/two-sum-iv-input-is-a-bst) | [![Java](assets/java.png)](src/TwoSumIVInputIsABST.java) [![Python](assets/python.png)](python/two_sum_iv.py) |
 | 657 | [Robot Return to Origin](https://leetcode.com/problems/robot-return-to-origin) | [![Java](assets/java.png)](src/RobotReturnToOrigin.java) [![Python](assets/python.png)](python/robot_return_to_origin.py) |
 | 661 | [Image Smoother](https://leetcode.com/problems/image-smoother) | [![Java](assets/java.png)](src/ImageSmoother.java) [![Python](assets/python.png)](python/image_smoother.py) |
+| 637 | [Average of Levels in Binary Tree](https://leetcode.com/problems/average-of-levels-in-binary-tree) | [![Java](assets/java.png)](src/AverageLevelsOfBinaryTree.java) [![Python](assets/python.png)](python/) |
+| 643 | [Maximum Average SubArray I](https://leetcode.com/problems/maximum-average-subarray-i) | |
+| 645 | [Set Mismatch](https://leetcode.com/problems/set-mismatch) | |
+| 653 | [Two Sum IV - Input is a BST](https://leetcode.com/problems/two-sum-iv-input-is-a-bst) | |
+| 657 | [Robot Return to Origin](https://leetcode.com/problems/robot-return-to-origin) | |
+| 661 | [Image Smoother](https://leetcode.com/problems/image-smoother) | |
 | 665 | [Non Deceasing Array](https://leetcode.com/problems/non-decreasing-array) | |
 | 669 | [Trim a Binary Search Tree](https://leetcode.com/problems/trim-a-binary-search-tree) | |
 | 671 | [Second Minimum Node in Binary Tree](https://leetcode.com/problems/second-minimum-node-in-a-binary-tree) | |

Diff for: src/AverageLevelsOfBinaryTree.java

@@ -0,0 +1,32 @@
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+
+public class AverageLevelsOfBinaryTree {
+    public List<Double> averageOfLevels(TreeNode root) {
+        Queue<TreeNode> queue = new LinkedList<>();
+        queue.add(root);
+        queue.add(null);
+        int count = 0;
+        List<Double> result = new ArrayList<>();
+        result.add(0.0);
+        while (!queue.isEmpty()) {
+            TreeNode current = queue.poll();
+            if (current == null && queue.isEmpty()) break;
+            if (current == null) {
+                queue.add(null);
+                result.set(result.size() - 1, result.get(result.size() - 1) / count);
+                result.add(0.0);
+                count = 0;
+                continue;
+            }
+            count++;
+            if (current.left != null) queue.add(current.left);
+            if (current.right != null) queue.add(current.right);
+            result.set(result.size() - 1, result.get(result.size() - 1) + current.val);
+        }
+        result.set(result.size() - 1, result.get(result.size() - 1) / count);
+        return result;
+    }
+}