return its bottom-up level order traversal as: [ [15,7], [9,20], [3] ] /** * Definition for binary tree * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ //与层序遍历的思想一模一样,唯一差别是在添加thisL...
从底部层序遍历其实还是从顶部开始遍历,只不过最后存储的方式有所改变,可以参见博主之前的博文Binary Tree Level Order Traversal, 参见代码如下: 解法一: classSolution {public: vector<vector<int> > levelOrderBottom(TreeNode*root) {if(!root)return{}; vector<vector<int>>res; queue<TreeNode*>q{{root}}...
public List<List<Integer>> levelOrder(TreeNode root) { List<List<Integer>> ans = new ArrayList<>(); DFS(root, 0, ans); return ans; } private void DFS(TreeNode root, int level, List<List<Integer>> ans) { if(root == null){ return; } //当前层数还没有元素,先 new 一个空的列表...
Binary Tree Level Order Traversal II Given a binary tree, return the bottom-up level order For example: Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9 20 / \ 15 7 return its bottom-up level order traversal as: [ [15,7], [9,20], [3] ] confused what ...
LeetCode Binary Tree Level Order Traversal II (二叉树颠倒层序),题意:从左到右统计将同一层的值放在同一个容器vector中,要求上下颠倒,左右不颠倒。思路:广搜逐层添加进来,最后再反转。1/**2*Definitionforabinarytreenode.3*structTreeNode{4*intval;5...
Memory Usage: 13.3 MB, less than 77.88% of Python3 online submissions for Binary Tree Level Order Traversal II. classSolution:deflevelOrderBottom(self,root:TreeNode)->List[List[int]]:ifroot==None:return[]value=[]node_ls=[root]defhelper(node_ls):cache=[]forninnode_ls:ifn.left!=None:ca...
Tree-E-102. Binary Tree Level Order Traversal 时间20180301 1.解法1 本题的实质是广度优先搜索BFS,而队列可以轻松的以迭代形式实现它,不过不同于BFS的是,层序便利需要在队列中记住每一层的分割点,而BFS不关心层数只要遍历到指定元素就行了。为了记住这个分割点,我们在进入下一层之前先记下这一层的元素...
Given the root of a binary tree, return the level order traversal of its nodes' values. (i.e., from left to right, level by level). Example 1: Input: root = [3,9,20,null,null,15,7] Output: [[3],[9,20],[15,7]] Example 2: Input: root = [1] Output: [[1]] Example ...
(即逐层地,从左到右访问所有节点)。 例如: 给定二叉树: [3,9,20,null,null,15,7], 返回其自底向上的层次遍历为: [ [15,7], [9,20], [3] ] 解题思路 该问题需要用到队列,解法与上篇每天一算:Binary Tree Level Order Traversal类似,区别在于最后存储方式的不同。
高频刷题-102. Binary Tree Level Order Traversal 和 103. Binary Tree Zigzag Level Order Traversal,程序员大本营,技术文章内容聚合第一站。