HDU 4292 Food (拆点最大流)

#include<bits/stdc++.h>
using namespace std;
#define captype int
const int MAXN = 1010;   
const int MAXM = 400010;    
const int INF = 1<<30;
struct EDGE{
    int to,next;
    captype cap;
} edg[MAXM];
int eid,head[MAXN];
int gap[MAXN];  
int dis[MAXN];  
int cur[MAXN];  
int pre[MAXN];
 
void init(){
    eid=0;
    memset(head,-1,sizeof(head));
}
void AddEdge(int u,int v,captype c,captype rc=0){
    edg[eid].to=v; edg[eid].next=head[u];
    edg[eid].cap=c;  head[u]=eid++;
    edg[eid].to=u; edg[eid].next=head[v];
    edg[eid].cap=rc; head[v]=eid++;
}
captype maxFlow_sap(int sNode,int eNode, int n){//n是包括源点和汇点的总点个数，这个一定要注意
    memset(gap,0,sizeof(gap));
    memset(dis,0,sizeof(dis));
    memcpy(cur,head,sizeof(head));
    pre[sNode] = -1;
    gap[0]=n;
    captype ans=0;  
    int u=sNode;
    while(dis[sNode]<n){   
        if(u==eNode){  
            captype Min=INF ;
            int inser;
            for(int i=pre[u]; i!=-1; i=pre[edg[i^1].to])    
            if(Min>edg[i].cap){
                Min=edg[i].cap;
                inser=i;
            }
            for(int i=pre[u]; i!=-1; i=pre[edg[i^1].to]){
                edg[i].cap-=Min;
                edg[i^1].cap+=Min;  
            }
            ans+=Min;
            u=edg[inser^1].to;
            continue;
        }
        bool flag = false; 
        int v;
        for(int i=cur[u]; i!=-1; i=edg[i].next){
            v=edg[i].to;
            if(edg[i].cap>0 && dis[u]==dis[v]+1){
                flag=true;
                cur[u]=pre[v]=i;
                break;
            }
        }
        if(flag){
            u=v;
            continue;
        }
        int Mind= n;
        for(int i=head[u]; i!=-1; i=edg[i].next)
        if(edg[i].cap>0 && Mind>dis[edg[i].to]){
            Mind=dis[edg[i].to];
            cur[u]=i;
        }
        gap[dis[u]]--;
        if(gap[dis[u]]==0) return ans;  
        dis[u]=Mind+1;
        gap[dis[u]]++;
        if(u!=sNode) u=edg[pre[u]^1].to;  //退一条边
    }
    return ans;
}
 
int main()
{
    #ifndef ONLINE_JUDGE
        freopen("in.txt","r",stdin);
        freopen("out.txt","w",stdout);
    #endif
    int S,T,N,M,F,D,u,v,tmp;
    while(scanf("%d%d%d",&N,&F,&D)==3){
        S=0,T=2*N+F+D+1;            //源点，汇点
        init();
        for(int i=1;i<=F;++i){
            scanf("%d",&tmp);
            AddEdge(S,i,tmp);
        }
        for(int i=1;i<=D;++i){
            scanf("%d",&tmp);
            AddEdge(F+N*2+i,T,tmp);
        }
        for(int i=1;i<=N;++i){
            AddEdge(i+F,i+F+N,1);
            char op[MAXN];      
            scanf("%s",op);      
            for(int j=1;j<=F;++j){
                if(op[j-1]==‘Y‘) AddEdge(j,i+F,1);
            }
        }
        for(int i=1;i<=N;++i){
            char op[MAXN];      
            scanf("%s",op);
            for(int j=1;j<=D;++j){
                if(op[j-1]==‘Y‘) AddEdge(F+N+i,F+N*2+j,1);
            }
        }
        printf("%d\n",maxFlow_sap(S,T,T+1));
    }
    return 0;
}