hdu 3435 A new Graph Game (有向环覆盖，拆点，二分图最优匹配，KM算法)

  1/* ***********************************************
  2Author :111qqz
  3Created Time :2016年06月02日 星期四 20时13分25秒
  4File Name :code/hdu/1853.cpp
  5************************************************ */
  6
  7#include <cstdio>
  8#include <cstring>
  9#include <iostream>
 10#include <algorithm>
 11#include <vector>
 12#include <queue>
 13#include <set>
 14#include <map>
 15#include <string>
 16#include <cmath>
 17#include <cstdlib>
 18#include <ctime>
 19#define fst first
 20#define sec second
 21#define lson l,m,rt<<1
 22#define rson m+1,r,rt<<1|1
 23#define ms(a,x) memset(a,x,sizeof(a))
 24typedef long long LL;
 25#define pi pair < int ,int >
 26#define MP make_pair
 27
 28using namespace std;
 29const double eps = 1E-8;
 30const int dx4[4]={1,0,0,-1};
 31const int dy4[4]={0,-1,1,0};
 32const int inf = 0x3f3f3f3f;
 33const int N=1E3+4;
 34int n,m;
 35bool visx[N],visy[N];
 36int link[N];
 37int lx[N],ly[N];
 38int slk[N];
 39int w[N][N];
 40
 41
 42bool find( int u)
 43{
 44    visx[u] = true;
 45    for ( int v = 1 ; v <= n ; v++)
 46    {
 47	if (visy[v]) continue;
 48	int tmp = lx[u] + ly[v] - w[u][v];
 49	if (tmp==0)
 50	{
 51	    visy[v] = true;
 52
 53	    if (link[v]==-1||find(link[v]))
 54	    {
 55		link[v] =  u;
 56		return true;
 57	    }
 58	}else if (tmp<slk[v]) slk[v] = tmp;
 59    }
 60    return false;
 61}
 62int KM()
 63{
 64    ms(lx,0xc0);
 65    ms(ly,0);
 66    ms(link,-1);
 67
 68    for ( int i = 1 ; i <= n ; i++)
 69	for ( int j = 1 ; j <= n ; j++)
 70	    lx[i] = max(lx[i],w[i][j]);
 71    for ( int i = 1 ; i <= n ; i++) if (lx[i]==-inf-1) return -1; //?
 72
 73    for ( int i = 1 ; i <= n ; i++)
 74    {
 75	ms(slk,0x3f);
 76
 77	while (1)
 78	{
 79	    ms(visx,false);
 80	    ms(visy,false);
 81
 82	    if (find(i)) break;
 83
 84	    int d = inf;
 85
 86	    for ( int j = 1 ; j <= n ; j++)
 87		if (!visy[j]&&slk[j]<d) d = slk[j];
 88
 89	    for ( int j = 1 ; j <= n ; j++)
 90		if (visx[j]) lx[j]-=d;
 91	    for ( int j = 1 ; j <= n ; j++)
 92		if (visy[j]) ly[j]+=d ; else slk[j]-=d;
 93	}
 94    }
 95    int res = 0 ;
 96
 97    for ( int i  = 1 ; i <= n ; i++)
 98	if (link[i]>-1) res += w[link[i]][i];
 99
100    return -res;
101
102}
103int main()
104{
105	#ifndef  ONLINE_JUDGE 
106	freopen("code/in.txt","r",stdin);
107  #endif
108	int T;
109	int cas = 0 ;
110	cin>>T;
111	while (T--)
112	{
113	    scanf("%d %d",&n,&m);
114	    ms(w,0xc0);
115	    for ( int i = 1 ; i <= m ; i++)
116	    {
117		int u,v,cost;
118		scanf("%d%d%d",&u,&v,&cost);
119		w[u][v] =max(w[u][v],-cost); //会不会有重边。..果然有。
120		w[v][u] =max(w[v][u],-cost);
121	    }
122
123	    int ans = KM();
124	    printf("Case %d: ",++cas);
125	    if (ans==-1) puts("NO");
126	    else printf("%d\n",ans);
127
128
129	}
130
131
132
133
134
135  #ifndef ONLINE_JUDGE  
136  fclose(stdin);
137  #endif
138    return 0;
139}