题意: 给出一个\(n\)个点\(m\)条边的无向图,现在要给若干个点染色,使得每条边都至少邻接一个被染色的顶点.问至少要给多少各点染色才能满足条件. 分析: 注意到题目中有一个很特殊的条件: 对于图中任意一条边\(u,v\),有\(min \{ u,v \} \leq 30\) 所以最坏的情况下,最多染30个点就可以满足条件. 所以用bitset维护一下当前被染色的点的情况即可. #include <cstdio> #include <cstring> #include <…

模式串为子串 KMP /* @author : victor */ #include <bits/stdc++.h> using namespace std; typedef long long ll; ; int next_[MAX]; char s1[MAX], s2[MAX], ans[MAX]; int pos[MAX]; int l1, l2, cnt; void get_next(char x[],int m,int next_[]) { int i ,j; j = next_[]…

这里将讲解一下npc问题中set cover和vertex cover分别是什么. set cover: 问题定义: 实例:现在有一个集合A,其中包含了m个元素(注意,集合是无序的,并且包含的元素也是不相同的),现在n个集合,分别为B1.B2.....Bn.并且这n个集合的并集恰好等于A集合,即:B1UB2UB3U...UBn=A. 问题:是否存在B集合的最小子集,且他们的并集也等于A集合? 例子:集合A={1,2,3,4,5},集合B={{1,2,3},{2,4},{3,4},{4,5}}.可…

2038. Minimum Vertex Cover Time limit: 1.0 secondMemory limit: 64 MB A vertex cover of a graph is a set of vertices such that each edge of the graph is incident to at least one vertex of the set. A minimum vertex cover is a vertex cover with minimal…

1134. Vertex Cover (25) 时间限制 600 ms 内存限制 65536 kB 代码长度限制 16000 B 判题程序 Standard 作者 CHEN, Yue A vertex cover of a graph is a set of vertices such that each edge of the graph is incident to at least one vertex of the set. Now given a graph with several…

A vertex cover of a graph is a set of vertices such that each edge of the graph is incident to at least one vertex of the set. Now given a graph with several vertex sets, you are supposed to tell if each of them is a vertex cover or not. Input Specif…

A vertex cover of a graph is a set of vertices such that each edge of the graph is incident to at least one vertex of the set. Now given a graph with several vertex sets, you are supposed to tell if each of them is a vertex cover or not. Input Specif…

https://pintia.cn/problem-sets/994805342720868352/problems/994805346428633088 A vertex cover of a graph is a set of vertices such that each edge of the graph is incident to at least one vertex of the set. Now given a graph with several vertex sets, y…

Vertex Cover Problem's Link Mean: 给你一个无向图,让你给图中的结点染色,使得:每条边的两个顶点至少有一个顶点被染色.求最少的染色顶点数. analyse: 裸的最小点覆盖问题,二分图的最大匹配,直接套模版即可. Time complexity: O(N^2) view code…

Vertex Cover frog has a graph with \(n\) vertices \(v(1), v(2), \dots, v(n)\) and \(m\) edges \((v(a_1), v(b_1)), (v(a_2), v(b_2)), \dots, (v(a_m), v(b_m))\). She would like to color some vertices so that each edge has at least one colored vertex. Fi…