bzoj 1391

 建图跑最小割,加当前弧优化。

  

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<queue>
 5 #include<algorithm>
 6 #define N 3000
 7 #define inf 0x3f3f3f3f
 8 #define M 4000005
 9 using namespace std;
10 int n,m;
11 int tot;
12 int head[N],nxt[M],ver[M],f[M];
13 void add(int a,int b,int c)
14 {
15     tot++;nxt[tot]=head[a];head[a]=tot;ver[tot]=b;f[tot]=c;
16     tot++;nxt[tot]=head[b];head[b]=tot;ver[tot]=a;f[tot]=0;
17 }
18 int S,T;
19 int ch[N];int cur[N];
20 int zeng(int a,int b)
21 {
22     if(a==T)return b;
23     int r=0;
24     for(int i=cur[a];i&&b>r;i=nxt[i])
25     {
26         if(ch[ver[i]]==ch[a]+1&&f[i])
27         {
28             int t=zeng(ver[i],min(b-r,f[i]));
29             r+=t;f[i]-=t;f[i^1]+=t;
30             if(f[i]>0)cur[a]=i;
31         }
32     }
33     if(!r)ch[a]=-1;
34     return r;
35 }
36 bool tell()
37 {
38     memset(ch,-1,sizeof(ch));
39     ch[S]=0;
40     queue<int>q;
41     q.push(S);
42     while(!q.empty())
43     {
44         int tmp=q.front();q.pop();
45         for(int i=head[tmp];i;i=nxt[i])
46         {
47             if(f[i]&&ch[ver[i]]==-1)
48             {
49                 ch[ver[i]]=ch[tmp]+1;
50                 q.push(ver[i]);
51             }
52         }
53     }
54     return ch[T]!=-1;
55 }
56 int dinic()
57 {
58     int r=0,t;
59     while(tell())
60     {
61         for(int i=0;i<=T;i++)cur[i]=head[i];
62        while(t=zeng(S,inf))r+=t;    
63     }
64     return r;
65 }
66 int v[N];
67 int ans;
68 int main()
69 {
70     tot=1;
71     scanf("%d%d",&n,&m);int t1,t2;
72     S=0;T=n+m+1;
73     for(int i=1;i<=n;i++)
74     {
75         int tmp;
76         scanf("%d%d",&v[i],&tmp);ans+=v[i];
77         add(i+m,T,v[i]);
78         for(int j=1;j<=tmp;j++)
79         {
80             scanf("%d%d",&t1,&t2);
81             add(t1,i+m,t2);
82         }
83     }
84     for(int i=1;i<=m;i++)
85     {
86         scanf("%d",&t1);
87         add(S,i,t1);
88     }
89     printf("%d
",ans-dinic());
90     return 0;
91 }
原文地址:https://www.cnblogs.com/ezyzy/p/6248049.html