Cyclic Tour Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/65535 K (Java/Others)Total Submission(s): 2399    Accepted Submission(s): 1231 Problem Description There are N cities in our country, and M one-way roads connecting them. Now L…

Cyclic Tour Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/65535 K (Java/Others)Total Submission(s): 1197    Accepted Submission(s): 626 Problem Description There are N cities in our country, and M one-way roads connecting them. Now Li…

http://acm.hdu.edu.cn/showproblem.php?pid=3488 题意: 给出n个点和m条边,每条边有距离,把这n个点分成1个或多个环,且每个点只能在一个环中,保证有解. 思路: 把一个点分成两部分,1~n和n+i~2*n. 连边的情况是这样的,(src,i,1,0),(i+n,dst,1,0). 如果两个点之间相同,则(i,j+n,1,d). 其实这道题目就是选n条边,如何使得权值之和最小. 具体请参考这http://blog.csdn.net/u013480600…

http://acm.hdu.edu.cn/showproblem.php?pid=3488 给一个无源汇的,带有边权的有向图 让你找出一个最小的哈密顿回路 可以用KM算法写,但是费用流也行 思路 1. 哈密顿回路对于每个点的流量有限制,因此$V$拆开为$V$和$V'$ 2. 我们建立附加源点$S$和附加汇点$T$哈密顿回路中的每个点有其唯一的后继和前驱,换句话说,对于任意一个点$V$,它满足$in(V)=out(V)$ 为了满足该条件,从源点向$V$ 连接容量为1,费用为0的边,从$V'$向汇…

链接:http://acm.hdu.edu.cn/showproblem.php?pid=1853 Cyclic Tour Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/65535 K (Java/Others) Total Submission(s): 1904    Accepted Submission(s): 951 Problem Description There are N cities in our c…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1853 There are N cities in our country, and M one-way roads connecting them. Now Little Tom wants to make several cyclic tours, which satisfy that, each cycle contain at least two cities, and each city b…

Problem Description There are N cities in our country, and M one-way roads connecting them. Now Little Tom wants to make several cyclic tours, which satisfy that, each cycle contain at least two cities, and each city belongs to one cycle exactly. Tom…

题意:给定N个点,M条边,M >= N-1.已知M条边都有一个权值,已知前N-1边能构成一颗N个节点生成树,现问通过修改这些边的权值使得最小生成树为前N条边的最小改动总和为多少? 分析:由于计算的最小改动且为最小生成树则显然前N-1条边肯定权值都减少,后面的边权值都增加.由于选择的边为前N-1得到最小生成树,因此首先将N-1条边构图,然后对后面的每一条边,那么这条边所构成的环中,有任意一条边的a与该边b,设原始权重为w[a],w[b],改变量为d[a],w[b],则有w[a] - d[a] <…

Cyclic Tour Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/65535 K (Java/Others) Total Submission(s): 1879    Accepted Submission(s): 938 Problem Description There are N cities in our country, and M one-way roads connecting them. Now L…

题目传送门 /* KM: 相比HDOJ_1533,多了重边的处理,还有完美匹配的判定方法 */ #include <cstdio> #include <cmath> #include <algorithm> #include <cstring> using namespace std; ; const int INF = 0x3f3f3f3f; int x[MAXN], y[MAXN]; int w[MAXN][MAXN]; int visx[MAXN],…