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  • SCU3109 Space flight(最大权闭合子图)

    嗯,裸的最大权闭合子图。

      1 #include<cstdio>
      2 #include<cstring>
      3 #include<queue>
      4 #include<algorithm>
      5 using namespace std;
      6 #define INF (1<<30)
      7 #define MAXN 111
      8 #define MAXM 111*222
      9 
     10 struct Edge{
     11     int v,cap,flow,next;
     12 }edge[MAXM];
     13 int vs,vt,NE,NV;
     14 int head[MAXN];
     15 
     16 void addEdge(int u,int v,int cap){
     17     edge[NE].v=v; edge[NE].cap=cap; edge[NE].flow=0;
     18     edge[NE].next=head[u]; head[u]=NE++;
     19     edge[NE].v=u; edge[NE].cap=0; edge[NE].flow=0;
     20     edge[NE].next=head[v]; head[v]=NE++;
     21 }
     22 
     23 int level[MAXN];
     24 int gap[MAXN];
     25 void bfs(){
     26     memset(level,-1,sizeof(level));
     27     memset(gap,0,sizeof(gap));
     28     level[vt]=0;
     29     gap[level[vt]]++;
     30     queue<int> que;
     31     que.push(vt);
     32     while(!que.empty()){
     33         int u=que.front(); que.pop();
     34         for(int i=head[u]; i!=-1; i=edge[i].next){
     35             int v=edge[i].v;
     36             if(level[v]!=-1) continue;
     37             level[v]=level[u]+1;
     38             gap[level[v]]++;
     39             que.push(v);
     40         }
     41     }
     42 }
     43 
     44 int pre[MAXN];
     45 int cur[MAXN];
     46 int ISAP(){
     47     bfs();
     48     memset(pre,-1,sizeof(pre));
     49     memcpy(cur,head,sizeof(head));
     50     int u=pre[vs]=vs,flow=0,aug=INF;
     51     gap[0]=NV;
     52     while(level[vs]<NV){
     53         bool flag=false;
     54         for(int &i=cur[u]; i!=-1; i=edge[i].next){
     55             int v=edge[i].v;
     56             if(edge[i].cap!=edge[i].flow && level[u]==level[v]+1){
     57                 flag=true;
     58                 pre[v]=u;
     59                 u=v;
     60                 //aug=(aug==-1?edge[i].cap:min(aug,edge[i].cap));
     61                 aug=min(aug,edge[i].cap-edge[i].flow);
     62                 if(v==vt){
     63                     flow+=aug;
     64                     for(u=pre[v]; v!=vs; v=u,u=pre[u]){
     65                         edge[cur[u]].flow+=aug;
     66                         edge[cur[u]^1].flow-=aug;
     67                     }
     68                     //aug=-1;
     69                     aug=INF;
     70                 }
     71                 break;
     72             }
     73         }
     74         if(flag) continue;
     75         int minlevel=NV;
     76         for(int i=head[u]; i!=-1; i=edge[i].next){
     77             int v=edge[i].v;
     78             if(edge[i].cap!=edge[i].flow && level[v]<minlevel){
     79                 minlevel=level[v];
     80                 cur[u]=i;
     81             }
     82         }
     83         if(--gap[level[u]]==0) break;
     84         level[u]=minlevel+1;
     85         gap[level[u]]++;
     86         u=pre[u];
     87     }
     88     return flow;
     89 }
     90 int read(char *&s){
     91     int res;
     92     if(sscanf(s,"%d",&res)!=1) return -1;
     93     while(*s==' ') ++s;
     94     while(*s>='0' && *s<='9') ++s;
     95     while(*s==' ') ++s;
     96     return res;
     97 }
     98 int main(){
     99     char str[1111];
    100     int n,m,a,b;
    101     while(~scanf("%d%d ",&m,&n)){
    102         vs=0; vt=n+m+1; NV=vt+1; NE=0;
    103         memset(head,-1,sizeof(head));
    104         int tot=0;
    105         for(int i=1; i<=m; ++i){
    106             gets(str);
    107             char *s=str;
    108             a=read(s); tot+=a;
    109             addEdge(vs,i,a);
    110             while(a=read(s),a!=-1) addEdge(i,a+m,INF);
    111         }
    112         for(int i=1; i<=n; ++i){
    113             scanf("%d",&a);
    114             addEdge(i+m,vt,a);
    115         }
    116         printf("%d
    ",tot-ISAP());
    117     }
    118     return 0;
    119 }
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  • 原文地址:https://www.cnblogs.com/WABoss/p/5342901.html
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