Find All the Lonely Nodes
给一个二叉树, 定一个lonely node是一个node只有一个child, 返回这些child. 用层序扫描即可.
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 |
/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode() {} * TreeNode(int val) { this.val = val; } * TreeNode(int val, TreeNode left, TreeNode right) { * this.val = val; * this.left = left; * this.right = right; * } * } */ class Solution { public List<Integer> getLonelyNodes(TreeNode root) { Queue<TreeNode> q = new LinkedList<>(); q.add(root); List<Integer> res = new ArrayList<>(); while(!q.isEmpty()) { int size = q.size(); for(int i = 0; i < size; i++) { TreeNode node = q.poll(); if(node.left != null && node.right == null) { res.add(node.left.val); } if(node.left == null && node.right != null) { res.add(node.right.val); } if(node.left != null) { q.add(node.left); } if(node.right != null) { q.add(node.right); } } } return res; } } |