HDU 4309 Contest 1

最大流建图。开始以为旧桥有1000座，没敢用枚举，后来看看题目发现了只是十二座。枚举桥的状态没问题。

对于隧道的容量W，可以虚拟出第三个结点表示，如u->v。增加一个点p,u->p（INF）,p->v(INF),p->End(W);

 

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>

using namespace std;

const int INF=0x3f3f3f3f;
const int MAXN=300;//点数的最大值
const int MAXM=5000;//边数的最大值

struct Node{
    int from,to,next;
    int cap;
}edge[MAXM];

struct Edge{
	int u,v,w;
}Tun[30],Acient[20],Modern[1000];

int tol;
int dep[MAXN];
int head[MAXN];
int val[MAXN];

void init(){
    tol=0;
    memset(head,-1,sizeof(head));
}
void addedge(int u,int v,int w){
    edge[tol].from=u;
    edge[tol].to=v; edge[tol].cap=w;  edge[tol].next=head[u];
    head[u]=tol++;
    edge[tol].from=v;
    edge[tol].to=u;
    edge[tol].cap=0;
    edge[tol].next=head[v];
    head[v]=tol++;
}

int BFS(int start,int end){
    int que[MAXN];
    int front,rear; front=rear=0;
    memset(dep,-1,sizeof(dep));
    que[rear++]=start;
    dep[start]=0;
    while(front!=rear){
        int u=que[front++];
        if(front==MAXN)front=0;
        for(int i= head[u];i!=-1; i=edge[i].next){
            int v=edge[i].to;
            if(edge[i].cap>0&& dep[v]==-1){
                dep[v]=dep[u]+1;
                que[rear++]=v;
                if(rear>=MAXN) rear=0;
                if(v==end)return 1;
            }
        }
    }
    return 0;
}

int dinic(int start,int end){
    int res=0;
    int top;
    int stack[MAXN];
    int cur[MAXN];
    while(BFS(start,end)){
        memcpy(cur,head, sizeof(head));
        int u=start;
        top=0;
        while(1){
            if(u==end){
                int min=INF;
                int loc;
               for(int i=0;i<top;i++)
                  if(min>edge [stack[i]].cap){
                      min=edge [stack[i]].cap;
                      loc=i;
                  }
                for(int i=0;i<top;i++){
                    edge[stack[i]].cap-=min;
                    edge[stack[i]^1].cap+=min;
                }
                res+=min;         
                top=loc;       
                u=edge[stack[top]].from;
            }
            for(int i=cur[u]; i!=-1; cur[u]=i=edge[i].next)        
              if(edge[i].cap!=0 && dep[u]+1==dep[edge[i].to])
                 break;
            if(cur[u] !=-1){
                stack [top++]= cur[u];
                u=edge[cur[u]].to;
            }
            else{
                if(top==0) break;   
                dep[u]=-1;
                u= edge[stack [--top] ].from;   
            }
        }
    }
    return res;
}

int main(){
	int n,e;
	int nT,nA,nM;
	int u,v,w,p;
	while(scanf("%d%d",&n,&e)!=EOF){
		nT=nA=nM=0;
		for(int i=1;i<=n;i++)
			scanf("%d",&val[i]);
		for(int i=0;i<e;i++){
			scanf("%d%d%d%d",&u,&v,&w,&p);
			if(p==0){
				Modern[nM].u=u;Modern[nM].v=v;
				Modern[nM].w=w;
				nM++;
			}
			else if(p<0){
				Tun[nT].u=u;Tun[nT].v=v;
				Tun[nT].w=w;
				nT++;
			}
			else{
				Acient[nA].u=u; Acient[nA].v=v;
				Acient[nA].w=w;
				nA++;
			}
		}
		int Start=0,End;
		End=n+nT+1;
		int len=(1<<nA);
		int cost,people,ansc=0,anspeople=0;
		for(int i=0;i<len;i++){
			init();
			cost=0;
			for(int k=1;k<=n;k++){
				addedge(Start,k,val[k]);
			}
			for(int k=0;k<nA;k++){
				if(i&(1<<k)){
					addedge(Acient[k].u,Acient[k].v,INF);
					cost+=Acient[k].w;
				}
				else 
				addedge(Acient[k].u,Acient[k].v,1);
			}
			for(int k=0;k<nM;k++){
				addedge(Modern[k].u,Modern[k].v,INF);
			}
			for(int k=0;k<nT;k++){	
				addedge(Tun[k].u,n+k+1,INF);
				addedge(n+k+1,Tun[k].v,INF);
				addedge(n+k+1,End,Tun[k].w);
			}
		//	system("pause");
			people=dinic(Start,End);
			if(people>anspeople){
				anspeople=people;
				ansc=cost;
			}
			else if(people==anspeople){
				ansc=min(cost,ansc);
			}
		}
		if(anspeople==0){
			printf("Poor Heaven Empire\n");
		}
		else
		printf("%d %d\n",anspeople,ansc);
	}
	return 0;
}