【BZOJ1497】[NOI2006]最大获利 最小割

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <queue>
 5 #include <cmath>
 6 #define inf 0x7fffffff
 7 #define hh 1e9
 8 #define M 60100
 9 using namespace std;
10 struct data
11 {
12     int v,next,to;
13 }e[M*6];
14 int head[M],deep[M],cur[M];
15 int n,m,cnt,sum,S,T;
16 inline int read()
17 {
18     int f=1,ans=0;
19     char c;
20     while (!isdigit(c=getchar())) if (c==‘-‘) f=-1;
21     ans=c-‘0‘;
22     while (isdigit(c=getchar())) ans=ans*10+c-‘0‘;
23     return ans*f;
24 }
25 inline void Add(int x,int y,int z)
26 {
27      e[cnt].next=head[x]; e[cnt].to=y; e[cnt].v=z; head[x]=cnt++; 
28      e[cnt].next=head[y]; e[cnt].to=x; e[cnt].v=0; head[y]=cnt++;
29 }
30 bool Bfs()
31 {
32     memset(deep,-1,sizeof(deep));
33     deep[0]=0;
34     //for (int i=0;i<=T;i++) cur[i]=head[i];
35     queue<int> q;
36     q.push(0);
37     while (!q.empty())
38     {
39         int now=q.front();q.pop();
40         for (int i=head[now];~i;i=e[i].next)
41             if (deep[e[i].to]==-1 && e[i].v)
42                 deep[e[i].to]=deep[now]+1,q.push(e[i].to);
43     }
44     return deep[T]!=-1;
45 }
46 int Dfs(int now,int flow)
47 {
48     if (now==T) return flow;
49     int used=0,f;
50     for (int i=cur[now];~i;i=e[i].next)
51     {
52         //cur[now]=i;
53         if (deep[e[i].to]==deep[now]+1)
54         {
55             f=Dfs(e[i].to,min(flow-used,e[i].v));
56             e[i].v-=f;
57             e[i^1].v+=f;
58             if (e[i].v) cur[now]=i;
59             used+=f;
60             //flow-=f;
61             if (used==flow) return flow;
62         }
63     }
64     if (!used) deep[now]=-1;
65     return used;
66 }
67 int Dinic()
68 {
69     int ans=0;
70     while (Bfs()) 
71     {
72         for (int i=S;i<=T;i++) cur[i]=head[i];
73         ans+=Dfs(S,inf);
74     }
75     return ans;
76 }
77 int x,y,z;
78 int main()
79 {
80     //memset(head,-1,sizeof(head));
81     n=read(); m=read();
82         S=0; T=n+m+1;
83     memset(head,-1,sizeof(head));
84     for (int i=1;i<=n;i++)
85     {
86         x=read();
87         Add(m+i,m+n+1,x);
88     }
89     for (int i=1;i<=m;i++)
90     {
91         //int x,y,z;
92         x=read(); y=read(); z=read();
93         sum+=z;
94         Add(i,m+x,inf); Add(i,m+y,inf);
95         Add(0,i,z);    
96     }
97     printf("%d\n",sum-Dinic());
98     return 0;
99 }