一、递归实现 1/**2* Definition for binary tree3* struct TreeNode {4* int val;5* TreeNode *left;6* TreeNode *right;7* TreeNode(int x) : val(x), left(NULL), right(NULL) {}8* };9*/10classSolution {11public:12vector<vector<int> > levelOrder(TreeNode *root) {13vector<vector...
Binary Tree Level Order Traversal 2 二叉树层序遍历 给一个二叉树的root,返回其节点值从低向上遍历,每一层从左到右 遍历。 Input: root = [3,9,20,null,null,15,7] Output: [[15,7],[9,20],[3]] /** * Definition for a binary tree node. * public class TreeNode { * int val; * Tree...
"");data=data.replace("}","");String[]vals=data.split(",");// INSERT ROOTTreeNoderoot=newTreeNode(Integer.parseInt(vals[0]));treeList.add(root);intindex=0;booleanisLeftChild=true;for(inti=1;i<vals.length;i++){if(!vals[i]...
Binary Tree Level Order Traversal Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). For example: Given binary tree [3,9,20,null,null,15,7], 3 / \ 9 20 / \ 15 7 return its level order traversal as: [[3],[...
return its level order traversal as: [ [3], [9,20], [15,7] ] 思路: 层序遍历二叉树是典型的广度优先搜索BFS的应用,但是这里稍微复杂一点的是,我们要把各个层的数分开,存到一个二维向量里面,大体思路还是基本相同的,建立一个queue,然后先把根节点放进去,这时候找根节点的左右两个子节点,这时候...
这道题考的就是 BFS,我们可以通过 DFS 实现。只需要在递归过程中将当前 level 传入即可。 publicList<List<Integer>>levelOrder(TreeNoderoot){List<List<Integer>>ans=newArrayList<>();DFS(root,0,ans);returnans;}privatevoidDFS(TreeNoderoot,intlevel,List<List<Integer>>ans){if(root==null){return;}...
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...
Given a binary tree, return thezigzag level ordertraversal of its nodes' values. (ie, from left to right, then right to left for the next level and alternate between). For example: Given binary tree{3,9,20,#,#,15,7}, 3 / \ ...
If you want to practice data structure and algorithm programs, you can go through 100+ java coding interview questions. 1. Introduction This article provides a detailed exploration of the Level Order traversal technique in binary trees, focusing on its implementation in Java. 2. What is Level Or...
For example, the maximum number of nodes in any level in the binary tree below is 4. Practice this problem 1. Iterative Approach In an iterative version, perform alevel order traversalon the tree. We can easily modify level order traversal to maintain the maximum number of nodes at the curr...