DFS 解法 ## 题目给定的 Node 类classNode:def__init__(self,val=0,neighbors=None):self.val=valifneighborsisNone:self.neighbors=[]else:self.neighbors=neighbors## 定义解题函数defcloneGraph(node):ifnotnode:returnnode# 创建一个字典来保存已经访问和克隆的节点visited={}# 定义DFS函数defdfs(node):ifn...
Given a 2d grid map of'1's (land) and'0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water. Example 1: Input: 11110 11...
虽然dfs/bfs这类题我是不太建议应届生或者刚入行的小朋友倾注过多的精力去刷的,一般来说,DFS这类问题相当于同学刷题进入了“深水区”。但是最近我看保offer班的同学的战报,发现题目难度直线上升,我决定还是多写一些相对复杂的题目。 我们建了一个微信群讨论群,我们在群里会分享一些 leetcode 的高效刷题方法和面...
Givennnodes labeled from0ton-1and a list of undirected edges (each edge is a pair of nodes), write a function to check whether these edges make up a valid tree. 这道题主要就是判断1.是否有环路 2. 是否是连通图 可以用DFS, BFS 和 Union find,union find最合适。 对于DFS和BFS,首先都是建...
本题与leetcode 787题几乎是一样的,不同之处在于787题限制了做多走k个结点,本题没有,也就是说,本题的路径最多可以走遍n个结点。由于边的数量会远大于结点数量,所以使用 Dijktra 算法比 Bellman-Ford 算法快。使用dfs是下下策,因为时间复杂度是 O(n^n),要疯狂剪枝,稍不留神就会超时。
PathsSourceTarget(vector<vector<int>>&graph){stk.push_back(0);dfs(graph,0,graph.size()-1);returnans;}};作者:LeetCode-Solution 链接:https://leetcode-cn.com/problems/all-paths-from-source-to-target/solution/suo-you-ke-neng-de-lu-jing-by-leetcode-s-iyoh/来源:力扣(LeetCode) 著作权归...
【LeetCode】137.克隆图(dfs+bfs,java实现) 题目 链接 解析 方法一:深度优先搜索 DFS 思想 注意:首先尝试将问题描述的更加清楚,使其便于理解。因为这个问题使我感到困惑,所以我决定编写该问题的题解,希望帮助读者弄清可能会遇到的疑问。 图中一个节点可以拥有任意数量的邻接点。为了避免在复制时陷入死循环,需要...
dfs(nei,graph,-colored,colors)) return false; }else if(colors[nei] == colored) return false; } return true; } 756. Pyramid Transition Matrix https://leetcode.com/problems/pyramid-transition-matrix/description/ 模拟题, 第一步,构造图,前2个字符为KEY,set<char> 为VALUE; 第二步,遍历bottom...
花花酱 LeetCode 2316. Count Unreachable Pairs of Nodes in an Undirected Graph By zxi on June 25, 2022 You are given an integern. There is anundirectedgraph withnnodes, numbered from0ton - 1. You are given a 2D integer arrayedgeswhereedges[i] = [ai, bi]denotes that there exists an...
原题链接在这里:https://leetcode.com/problems/unique-paths-iii/ 题目: On a 2-dimensional grid, there are 4 types of squares: 1 represents the starting square. There is exactly one starting square. 2 represents the ending square. There is exactly one ending s ...