HDU 3917 最大权闭合图 求最小割

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<vector>
 4 #define N 8005
 5 #define M 1000005
 6 #define inf 999999999
 7 #define min(a,b) ((a)<(b)?(a):(b))
 8 using namespace std;
 9 
10 int n,m,s,t,num;
11 int adj[N],dis[N],q[N];
12 vector<int> st[1005],ed[1005];
13 struct edge{
14     int v,w,pre;
15 }e[M];
16 void insert(int u,int v,int w){
17     e[num]=(edge){v,w,adj[u]};
18     adj[u]=num++;
19     e[num]=(edge){u,0,adj[v]};
20     adj[v]=num++;
21 }
22 
23 int bfs(){
24     int i,x,v,head=0,tail=0;
25     memset(dis,0,sizeof(dis));
26     dis[s]=1;
27     q[tail++]=s;
28     while(head<tail){
29         x=q[head++];
30         for(i=adj[x];~i;i=e[i].pre)
31             if(e[i].w&&!dis[v=e[i].v]){
32                 dis[v]=dis[x]+1;
33                 if(v==t)
34                     return 1;
35                 q[tail++]=v;
36             }
37     }
38     return 0;
39 }
40 int dfs(int x,int limit){
41     if(x==t)
42         return limit;
43     int i,v,tmp,cost=0;
44     for(i=adj[x];~i&&cost<limit;i=e[i].pre)
45         if(e[i].w&&dis[x]==dis[v=e[i].v]-1){
46             tmp=dfs(v,min(limit-cost,e[i].w));
47             if(tmp){
48                 e[i].w-=tmp;
49                 e[i^1].w+=tmp;
50                 cost+=tmp;
51             }
52             else
53                 dis[v]=-1;
54         }
55     return cost;
56 }
57 int Dinic(){
58     int ans=0;
59     while(bfs())
60         ans+=dfs(s,inf);
61     return    ans;
62 }
63 
64 int main(){
65     while(scanf("%d%d",&n,&m),n+m){
66         int i,j,k,u,v,c,w[5005]={0},sum=0;
67         num=0;
68         memset(adj,-1,sizeof(adj));
69         s=0;
70         t=1;
71         for(i=1;i<=n;i++){
72             st[i].clear();
73             ed[i].clear();
74         }
75         for(i=1;i<=m;i++){
76             scanf("%d",w+i);
77             sum+=w[i];
78             insert(i+1,t,w[i]);
79         }
80         scanf("%d",&k);
81         for(i=1;i<=k;i++){
82             scanf("%d%d%d%d",&u,&v,&c,&w[0]);
83             insert(s,i+m+1,w[0]);
84             insert(i+m+1,c+1,inf);
85             st[u].push_back(c);
86             ed[v].push_back(c);
87         }
88         for(i=1;i<=n;i++){
89             for(j=0;j<ed[i].size();j++){
90                 for(k=0;k<st[i].size();k++){
91                     insert(st[i][k]+1,ed[i][j]+1,inf);
92                     //printf("%d %d %d\n",i,ed[i][j],st[i][k]);
93                 }
94             }
95         }
96         printf("%d\n",sum-Dinic());
97     }
98 }