feat: add 637 AverageOfLevelsInBinaryTree

Author: nphausg

.idea/misc.xml

@@ -0,0 +1,36 @@
+package com.nphausg.leetcode.easy;
+
+import com.nphausg.leetcode.utils.TreeNode;
+
+import java.util.*;
+
+/**
+ * <a href="https://leetcode.com/problems/average-of-levels-in-binary-tree">637. Average of Levels in Binary Tree</a>
+ */
+public class AverageOfLevelsInBinaryTree {
+    public List<Double> averageOfLevels(TreeNode root) {
+        List<Double> result = new ArrayList<>();
+        if (root == null) {
+            return Collections.emptyList();
+        }
+        Queue<TreeNode> queue = new LinkedList<>();
+        queue.offer(root);
+        while (!queue.isEmpty()) {
+            long sum = 0;
+            int size = queue.size();
+            List<Integer> level = new ArrayList<>();
+            for (int i = 0; i < size; i++) {
+                TreeNode node = queue.poll();
+                sum += node.val;
+                if (node.left != null) {
+                    queue.offer(node.left);
+                }
+                if (node.right != null) {
+                    queue.offer(node.right);
+                }
+            }
+            result.add(sum / (double) size);
+        }
+        return result;
+    }
+}