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…

传送门 Vertex Cover frog has a graph with n vertices v(1),v(2),…,v(n)v(1),v(2),…,v(n) and m edges (v(a1),v(b1)),(v(a2),v(b2)),…,(v(am),v(bm))(v(a1),v(b1)),(v(a2),v(b2)),…,(v(am),v(bm)). She would like to color some vertices so that each edge has at leas…

Vertex Cover frog has a graph with nn vertices v(1),v(2),…,v(n)v(1),v(2),…,v(n) and mm edges (v(a1),v(b1)),(v(a2),v(b2)),…,(v(am),v(bm))(v(a1),v(b1)),(v(a2),v(b2)),…,(v(am),v(bm)). She would like to color some vertices so that each edge has at least…

题意: 给出n个点,m条边,将若干个点染色,使得每个边至少有一点染色,问至少染多少个点. 思路: 如果是二分图,那就是最小点覆盖,但是这是一般图. 一般图的最小覆盖是npc问题,但是这题有一个条件比较特殊,就是输入的每条边都保证了至少有一个点小于等于30,所以至多覆盖30个点就可以了. 那么就可以用搜索解决,对于一个点,要么覆盖,要么不覆盖. 如果这个点被覆盖了,就直接往下搜: 如果没有被覆盖,那么就要么覆盖这个点,直接往下搜:要么不覆盖这个点,但把这个点相邻的点全部覆盖,再往下搜. 得剪枝,可…

题意:每一条边至少有一个端点要涂颜色,问最少涂几个点 思路:最小顶点覆盖:用最少的点,让每条边都至少和其中一个点关联,显然是道裸最小顶点覆盖题: 参考:二分图 代码: #include<iostream> #include<algorithm> #include<cstdio> #include<stdio.h> #include<string.h> #include<queue> #include<cmath> #inc…

给你一个一般图 保证每条边的一端下标不大于30 问最小覆盖集的大小为多少 爆搜:枚举前30个点是否在覆盖集内 剪枝1:如果不在的话 那么他所连的下标大于30的点都必须选 剪纸2:最优解剪枝 #include<bits/stdc++.h> using namespace std; int n, m; bitset<> G[], em; int cnt, ans; > a) { if (a.count() >= ans) { return; } || o > ) {…

Jewelry Exhibition 时间限制: 1 Sec  内存限制: 64 MB提交: 3  解决: 3[提交][状态][讨论版] 题目描述 To guard the art jewelry exhibition at night, the security agency has decided to use a new laser beam system, consisting of sender-receiver pairs. Each pair generates a strip o…

[pixiv] https://www.pixiv.net/member_illust.php?mode=medium&illust_id=54859604 向大(hei)佬(e)势力学(di)习(tou) 二分图其实早就学了,可是无赖自己当初没好好听讲,变种就不说了,连匈牙利算法都不会.这次给了我一个好好复习改过自新的机会,既把匈牙利搞熟了,也算是理解了一些变种. 最小路径覆盖: 题意 用最少的出租车送完所有的乘客 将时间上可以接上的乘客连边 在一个图中,希望用最少的路径将所有点走遍,为什么…

Asteroids Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 24789   Accepted: 13439 Description Bessie wants to navigate her spaceship through a dangerous asteroid field in the shape of an N x N grid (1 <= N <= 500). The grid contains K a…

//匈牙利算法-DFS //求最小点覆盖集 == 求最大匹配 //Time:0Ms Memory:208K #include<iostream> #include<cstring> #include<cstdio> #include<algorithm> using namespace std; #define MAX 105 #define INF 0x3f3f3f3f int n,m,k; int gp[MAX][MAX]; bool sx[MAX],s…