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=0;
    edge[NE].next=head[u]; head[u]=NE++;
    edge[NE].v=u; edge[NE].cap=0; edge[NE].flow=0;
    edge[NE].next=head[v]; head[v]=NE++;
}

int level[MAXN];
int gap[MAXN];
void bfs(){
    memset(level,-1,sizeof(level));
    memset(gap,0,sizeof(gap));
    level[vt]=0;
    gap[level[vt]]++;
    queue<int> que;
    que.push(vt);
    while(!que.empty()){
        int u=que.front(); que.pop();
        for(int i=head[u]; i!=-1; i=edge[i].next){
            int v=edge[i].v;
            if(level[v]!=-1) continue;
            level[v]=level[u]+1;
            gap[level[v]]++;
            que.push(v);
        }
    }
}

int pre[MAXN];
int cur[MAXN];
int ISAP(){
    bfs();
    memset(pre,-1,sizeof(pre));
    memcpy(cur,head,sizeof(head));
    int u=pre[vs]=vs,flow=0,aug=INF;
    gap[0]=NV;
    while(level[vs]<NV){
        bool flag=false;
        for(int &i=cur[u]; i!=-1; i=edge[i].next){
            int v=edge[i].v;
            if(edge[i].cap!=edge[i].flow && level[u]==level[v]+1){
                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]^1].flow-=aug;
                    }
                    //aug=-1;
                    aug=INF;
                }
                break;
            }
        }
        if(flag) continue;
        int minlevel=NV;
        for(int i=head[u]; i!=-1; 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]]==0) break;
        level[u]=minlevel+1;
        gap[level[u]]++;
        u=pre[u];
    }
    return flow;
}
int d[MAXN],low[366][1111];
int main(){
    int n,m,a,b,c,l,r;
    while(~scanf("%d%d",&n,&m)){
        memset(d,0,sizeof(d));
        int S=0,T=n+m+1;
        vs=T+1; vt=vs+1; NV=vt+1; NE=0;
        memset(head,-1,sizeof(head));
        for(int i=1; i<=m; ++i){
            scanf("%d",&a);
            addEdge(i+n,T,INF);
            d[T]-=a;
            d[i+n]+=a;
        }
        memset(low,0,sizeof(low));
        vector<int> target[366];
        for(int i=1; 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=0;
        for(int i=S; i<=T; ++i){
            if(d[i]<0) addEdge(vs,i,-d[i]);
            else addEdge(i,vt,d[i]),tot+=d[i];
        }
tagEnd:
        if(ISAP()!=tot){
            puts("-1
");
            continue;
        }
        for(int i=tag; i<NE; ++i){
            edge[i].cap=edge[i].flow=0;
        }
        vs=S; vt=T;
        ISAP();
        tot=0;
        for(int i=head[vs]; i!=-1; i=edge[i].next){
            if(i&1) continue;
            tot+=edge[i].flow;
        }
        printf("%d
",tot);
        for(int u=1; u<=n; ++u){
            for(int i=head[u]; i!=-1; i=edge[i].next){
                int v=edge[i].v-n;
                if(i&1 || v<1 || v>m) continue;
                low[u][v]+=edge[i].flow;
            }
        }
        for(int u=1; u<=n; ++u){
            for(int i=0; i!=target[u].size(); ++i){
                printf("%d
",low[u][target[u][i]]);
            }
        }
        putchar('
');
    }
    return 0;
}