https://www.geeksforgeeks.org/bfs-vs-dfs-binary-tree/ What are BFS and DFS for Binary Tree? A Tree is typically traversed in two ways: Breadth First Traversal (Or Level Order Traversal) Depth First Traversals Inorder Traversal (Left-Root-Right) Preor…

题目描述 如下图, 有12张连在一起的12生肖的邮票.现在你要从中剪下5张来,要求必须是连着的.(仅仅连接一个角不算相连)  比如,下面两张图中,粉红色所示部分就是合格的剪取.  请你计算,一共有多少种不同的剪取方法.  输出 请填写表示方案数目的整数.    分析1           使用开锁解锁机制.通过DFS一边搜索一边计数,每积累5个方格就停止进一步搜索,同时将结果存储起来. 但是3.5.6.7.10(如图)此种情况是DFS做不到的,以下代码只用了DFS,只能得到82种结果. #inc…

题目: Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root). For example:Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9 20 / \ 15 7 return its bottom-up level orde…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 DFS BFS 日期 题目描述 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,nul…

#-*- coding: UTF-8 -*-#广度优先遍历# Definition for a binary tree node.# class TreeNode(object):#     def __init__(self, x):#         self.val = x#         self.left = None#         self.right = Noneclass Solution(object):    tmplist1=[]        def dfsDept…

题目: Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom. For example:Given the following binary tree, 1 <--- / \ 2 3 <--- \ \ 5 4 <--- You should return [1,…

题意: 给一棵二叉树,要求收集每层的最后一个节点的值.按从顶到底装进vector返回. 思路: BFS比较简单,先遍历右孩子就行了. /** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solut…

Oil Deposits Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 8274 Accepted Submission(s): 4860 Problem Description The GeoSurvComp geologic survey company is responsible for detecting underground…

Pet Time Limit: 4000/2000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 535 Accepted Submission(s): 258 Problem Description One day, Lin Ji wake up in the morning and found that his pethamster escaped. He searched in…

Given a binary tree, find its maximum depth. The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node. Note: A leaf is a node with no children. Example: Given binary tree [3,9,20,null,null,15,7…

Given a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node. Note: A leaf is a node with no children. Example: Given binary tree [3,9,20,null,null,15,7…

1.二叉树定义 // Definition for a binary tree node. struct TreeNode { int val; TreeNode *left; TreeNode *right; TreeNode(int x) : val(x), left(NULL), right(NULL) {} }; 2.遍历 a.递归先序: //递归先序: 中左右.PS:中序-左中右,后序-左右中,调换cout的位置即可 void NLR(TreeNode* T) { if(T!=NULL…

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,#,#,15,7}, 3 / \ 9 20 / \ 15 7 return its level order traversal as: [ [3], [9,20], [15,7] ] /*…

Leetcode之深度优先搜索(DFS)专题-199. 二叉树的右视图(Binary Tree Right Side View) 深度优先搜索的解题详细介绍,点击 给定一棵二叉树,想象自己站在它的右侧,按照从顶部到底部的顺序,返回从右侧所能看到的节点值. 示例: 输入: [1,2,3,null,5,null,4] 输出: [1, 3, 4] 解释: 1 <--- / \ 2 3 <--- \ \ 5 4 <--- 分析:把每一行的值保存起来,最后再把每一行最后一个放进ans里. AC代码…

Red and Black Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 6762 Accepted Submission(s): 4284 Problem Description There is a rectangular room, covered with square tiles. Each tile is colored eit…

https://leetcode.com/problems/binary-tree-right-side-view/ Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom. For example: Given the following binary tree, 1…

BFS solution is intuitive - here I will show a DFS based solution: /** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solut…

找到所有根到叶子的路径 深度优先搜索(DFS), 即二叉树的先序遍历. /** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solution { public: vector<string> v…

Given a binary tree, return the zigzag level order traversal 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 / \ 9 20 / \ 15 7 return its…

题意是倒过来层次遍历二叉树 下面我介绍下BFS的基本框架,所有的BFS都是这样写的 struct Nodetype { int d;//层数即遍历深度 KeyType m;//相应的节点值 } queue<Nodetype> q; q.push(firstnode); while(!q.empty()){ Nodetype now = q.front(); q.pop(); ........ for(遍历所有now点的相邻点next){ if(!visit[next]) { 访问每个没有访问过…

题意:给一棵二叉树,要求找出任意两个节点(也可以只是一个点)的最大路径和,至少1个节点,返回路径和.(点权有负的.) 思路:DFS解决,返回值是,经过从某后代节点上来到当前节点且路径和最大的值.要注意如果子树传来的如果是负值,是可以同时丢弃的,但至少要将当前节点的val更新答案. /** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right;…

https://leetcode.com/problems/binary-tree-maximum-path-sum/ Given a binary tree, find the maximum path sum. For this problem, a path is defined as any sequence of nodes from some starting node to any node in the tree along the parent-child connection…

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], [9,20], [15,7…

In a binary tree, the root node is at depth 0, and children of each depth knode are at depth k+1. Two nodes of a binary tree are cousins if they have the same depth, but have different parents. We are given the root of a binary tree with unique value…

Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom. Example: Input: [1,2,3,null,5,null,4] Output: [1, 3, 4] Explanation: 1 <--- / \ 2 3 <--- \ \ 5 4 <-----…

Given a non-empty binary tree, find the maximum path sum. For this problem, a path is defined as any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The path must contain at least one node and doe…

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], [9,20], [15,…

Given a binary tree, you need to find the length of Longest Consecutive Path in Binary Tree. Especially, this path can be either increasing or decreasing. For example, [1,2,3,4] and [4,3,2,1] are both considered valid, but the path [1,2,4,3] is not v…

Given a binary tree, find the length of the longest consecutive sequence path. The path refers to any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The longest consecutive path need to be from p…

Given a binary tree, return all root-to-leaf paths. Note: A leaf is a node with no children. Example: Input: 1 / \ 2 3 \ 5 Output: ["1->2->5", "1->3"] Explanation: All root-to-leaf paths are: 1->2->5, 1->3 思路为DFS, 只是a…