POJ3308 Paratroopers（最小割/最小点权覆盖）

  1 #include<cstdio>
  2 #include<cstring>
  3 #include<cmath>
  4 #include<queue>
  5 #include<algorithm>
  6 using namespace std;
  7 #define INF (1<<30)
  8 #define MAXN 111
  9 #define MAXM 1111
 10 
 11 struct Edge{
 12     int v,cap,flow,next;
 13 }edge[MAXM];
 14 int vs,vt,NE,NV;
 15 int head[MAXN];
 16 
 17 void addEdge(int u,int v,int cap){
 18     edge[NE].v=v; edge[NE].cap=cap; edge[NE].flow=0;
 19     edge[NE].next=head[u]; head[u]=NE++;
 20     edge[NE].v=u; edge[NE].cap=0; edge[NE].flow=0;
 21     edge[NE].next=head[v]; head[v]=NE++;
 22 }
 23 
 24 int level[MAXN];
 25 int gap[MAXN];
 26 void bfs(){
 27     memset(level,-1,sizeof(level));
 28     memset(gap,0,sizeof(gap));
 29     level[vt]=0;
 30     gap[level[vt]]++;
 31     queue<int> que;
 32     que.push(vt);
 33     while(!que.empty()){
 34         int u=que.front(); que.pop();
 35         for(int i=head[u]; i!=-1; i=edge[i].next){
 36             int v=edge[i].v;
 37             if(level[v]!=-1) continue;
 38             level[v]=level[u]+1;
 39             gap[level[v]]++;
 40             que.push(v);
 41         }
 42     }
 43 }
 44 
 45 int pre[MAXN];
 46 int cur[MAXN];
 47 int ISAP(){
 48     bfs();
 49     memset(pre,-1,sizeof(pre));
 50     memcpy(cur,head,sizeof(head));
 51     int u=pre[vs]=vs,flow=0,aug=INF;
 52     gap[0]=NV;
 53     while(level[vs]<NV){
 54         bool flag=false;
 55         for(int &i=cur[u]; i!=-1; i=edge[i].next){
 56             int v=edge[i].v;
 57             if(edge[i].cap!=edge[i].flow && level[u]==level[v]+1){
 58                 flag=true;
 59                 pre[v]=u;
 60                 u=v;
 61                 //aug=(aug==-1?edge[i].cap:min(aug,edge[i].cap));
 62                 aug=min(aug,edge[i].cap-edge[i].flow);
 63                 if(v==vt){
 64                     flow+=aug;
 65                     for(u=pre[v]; v!=vs; v=u,u=pre[u]){
 66                         edge[cur[u]].flow+=aug;
 67                         edge[cur[u]^1].flow-=aug;
 68                     }
 69                     //aug=-1;
 70                     aug=INF;
 71                 }
 72                 break;
 73             }
 74         }
 75         if(flag) continue;
 76         int minlevel=NV;
 77         for(int i=head[u]; i!=-1; i=edge[i].next){
 78             int v=edge[i].v;
 79             if(edge[i].cap!=edge[i].flow && level[v]<minlevel){
 80                 minlevel=level[v];
 81                 cur[u]=i;
 82             }
 83         }
 84         if(--gap[level[u]]==0) break;
 85         level[u]=minlevel+1;
 86         gap[level[u]]++;
 87         u=pre[u];
 88     }
 89     return flow;
 90 }
 91 int main(){
 92     double f;
 93     int t,n,m,l,a,b;
 94     scanf("%d",&t);
 95     while(t--){
 96         scanf("%d%d%d",&n,&m,&l);
 97         vs=0; vt=n+m+1; NV=vt+1; NE=0;
 98         memset(head,-1,sizeof(head));
 99         for(int i=1; i<=n; ++i){
100             scanf("%f",&f);
101             addEdge(vs,i,log10(f));
102         }
103         for(int i=1; i<=m; ++i){
104             scanf("%f",&f);
105             addEdge(i+n,vt,log10(f));
106         }
107         while(l--){
108             scanf("%d%d",&a,&b);
109             addEdge(a,b+n,INF);
110         }
111         printf("%.4f\n",pow(10,ISAP()));
112     }
113     return 0;
114 }