标签：enc nat ati ini not style range new ble
Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array.
Example 1:
Input:
3
/ 9 20
/ 15 7
Output: [3, 14.5, 11]
Explanation:
The average value of nodes on level 0 is 3, on level 1 is 14.5, and on level 2 is 11. Hence return [3, 14.5, 11].
Note:
按层遍历，求每层平均值。
/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ import java.util.LinkedList; import java.util.Queue; public class Solution { public List<Double> averageOfLevels(TreeNode root) { List<Double> retList = new ArrayList<Double>(); if (root == null) return retList; Queue<TreeNode> q = new LinkedList<TreeNode>(); q.offer(root); while ( ! q.isEmpty() ) { List<TreeNode> tl = new ArrayList<TreeNode>(); double sum = 0; while ( ! q.isEmpty() ) { TreeNode curr = q.poll(); tl.add(curr); sum += (double) curr.val; } retList.add(sum / tl.size()); for (TreeNode n : tl) { if (n.left != null) q.offer(n.left); if (n.right != null) q.offer(n.right); } } return retList; } }
637. Average of Levels in Binary Tree
标签：enc nat ati ini not style range new ble
原文地址：http://www.cnblogs.com/wxisme/p/7300360.html
