ZOJ3229 Shoot the Bullet（有源汇流量有上下界网络的最大流）

题目大概说在n天里给m个女孩拍照，每个女孩至少要拍G_i张照片，每一天最多拍D_k张相片且都有C_k个拍照目标，每一个目标拍照的张数要在[L_ki, R_ki]范围内，问最多能拍几张照片。

源点-天-女孩-汇点，这样子建容量网络。然后就是求这个有源汇流量有上下界容量网络的最大流：

• 首先计算其可行流，POJ2396
• 然后删除附加源、附加汇以及汇点到源点容量INF的边
• 最后从源点到汇点跑一边最大流即可

 #include<cstdio>
 #include<cstring>
 #include<vector>
 #include<queue>
 #include<algorithm>
 using namespace std;
 #define INF (1<<30)
 #define MAXN 2222
 #define MAXM 444*2222

 struct Edge{
     int v,cap,flow,next;
 }edge[MAXM];
 int vs,vt,NE,NV;
 int head[MAXN];

 void addEdge(int u,int v,int cap){
     edge[NE].v=v; edge[NE].cap=cap; edge[NE].flow=;
     edge[NE].next=head[u]; head[u]=NE++;
     edge[NE].v=u; edge[NE].cap=; edge[NE].flow=;
     edge[NE].next=head[v]; head[v]=NE++;
 }

 int level[MAXN];
 int gap[MAXN];
 void bfs(){
     memset(level,-,sizeof(level));
     memset(gap,,sizeof(gap));
     level[vt]=;
     gap[level[vt]]++;
     queue<int> que;
     que.push(vt);
     while(!que.empty()){
         int u=que.front(); que.pop();
         for(int i=head[u]; i!=-; i=edge[i].next){
             int v=edge[i].v;
             if(level[v]!=-) continue;
             level[v]=level[u]+;
             gap[level[v]]++;
             que.push(v);
         }
     }
 }

 int pre[MAXN];
 int cur[MAXN];
 int ISAP(){
     bfs();
     memset(pre,-,sizeof(pre));
     memcpy(cur,head,sizeof(head));
     int u=pre[vs]=vs,flow=,aug=INF;
     gap[]=NV;
     while(level[vs]<NV){
         bool flag=false;
         for(int &i=cur[u]; i!=-; i=edge[i].next){
             int v=edge[i].v;
             if(edge[i].cap!=edge[i].flow && level[u]==level[v]+){
                 flag=true;
                 pre[v]=u;
                 u=v;
                 //aug=(aug==-1?edge[i].cap:min(aug,edge[i].cap));
                 aug=min(aug,edge[i].cap-edge[i].flow);
                 if(v==vt){
                     flow+=aug;
                     for(u=pre[v]; v!=vs; v=u,u=pre[u]){
                         edge[cur[u]].flow+=aug;
                         edge[cur[u]^].flow-=aug;
                     }
                     //aug=-1;
                     aug=INF;
                 }
                 break;
             }
         }
         if(flag) continue;
         int minlevel=NV;
         for(int i=head[u]; i!=-; i=edge[i].next){
             int v=edge[i].v;
             if(edge[i].cap!=edge[i].flow && level[v]<minlevel){
                 minlevel=level[v];
                 cur[u]=i;
             }
         }
         if(--gap[level[u]]==) break;
         level[u]=minlevel+;
         gap[level[u]]++;
         u=pre[u];
     }
     return flow;
 }
 int d[MAXN],low[][];
 int main(){
     int n,m,a,b,c,l,r;
     while(~scanf("%d%d",&n,&m)){
         memset(d,,sizeof(d));
         int S=,T=n+m+;
         vs=T+; vt=vs+; NV=vt+; NE=;
         memset(head,-,sizeof(head));
         for(int i=; i<=m; ++i){
             scanf("%d",&a);
             addEdge(i+n,T,INF);
             d[T]-=a;
             d[i+n]+=a;
         }
         memset(low,,sizeof(low));
         vector<int> target[];
         for(int i=; i<=n; ++i){
             scanf("%d%d",&c,&a);
             addEdge(S,i,a);
             while(c--){
                 scanf("%d%d%d",&a,&l,&r);
                 ++a;
                 target[i].push_back(a); low[i][a]=l;
                 addEdge(i,a+n,r-l);
                 d[a+n]-=l;
                 d[i]+=l;
             }
         }
 int tag=NE;
         addEdge(T,S,INF);
         int tot=;
         for(int i=S; i<=T; ++i){
             if(d[i]<) addEdge(vs,i,-d[i]);
             else addEdge(i,vt,d[i]),tot+=d[i];
         }
 tagEnd:
         if(ISAP()!=tot){
             puts("-1\n");
             continue;
         }
         for(int i=tag; i<NE; ++i){
             edge[i].cap=edge[i].flow=;
         }
         vs=S; vt=T;
         ISAP();
         tot=;
         for(int i=head[vs]; i!=-; i=edge[i].next){
             if(i&) continue;
             tot+=edge[i].flow;
         }
         printf("%d\n",tot);
         for(int u=; u<=n; ++u){
             for(int i=head[u]; i!=-; i=edge[i].next){
                 int v=edge[i].v-n;
                 if(i& || v< || v>m) continue;
                 low[u][v]+=edge[i].flow;
             }
         }
         for(int u=; u<=n; ++u){
             for(int i=; i!=target[u].size(); ++i){
                 printf("%d\n",low[u][target[u][i]]);
             }
         }
         putchar('\n');
     }
     return ;
 }