【最大流FF模板】HDU1532&POJ1273

参照《挑战程序设计竞赛》

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstdlib>
 4 #include<cstring>
 5 #include<algorithm>
 6 #include<cmath>
 7 #include<vector>
 8 using namespace std;
 9 const int MAXN=1100;
10 const int INF=0x7fffffff;
11 int n,m;//n:edges,m:points 
12 struct node
13 {
14        int to,pos,cap;
15 };
16 vector<node> E[MAXN];
17 int vis[MAXN];
18 
19 void addedge(int u,int v,int w)
20 {
21      E[u].push_back((node){v,E[v].size(),w});
22      E[v].push_back((node){u,E[u].size()-1,0});
23 }
24 
25 int dfs(int s,int t,int f)
26 {
27     if (s==t) return f;
28     vis[s]=1;//不要忘记这里要设置为访问过 
29     for (int i=0;i<E[s].size();i++)
30     {
31         node &tmp=E[s][i]; 
32         if (vis[tmp.to]==0 && tmp.cap>0)
33         {
34             int delta=dfs(tmp.to,t,min(tmp.cap,f));
35             if (delta>0)
36             {
37                tmp.cap-=delta;
38                E[tmp.to][tmp.pos].cap+=delta;
39                return delta; 
40             }
41         }
42     }
43     return 0;
44 }
45 
46 int maxflow(int u,int v)
47 {
48     int flow=0;
49     for (;;)
50     {
51         memset(vis,0,sizeof(vis));
52         int f=dfs(u,v,INF);
53         if (f==0) return flow;
54            else flow+=f; 
55     }
56 }
57 
58 int main()
59 {
60     while(~scanf("%d%d",&n,&m))
61     {
62           memset(E,0,sizeof(E));
63           for (int i=0;i<n;i++)
64           {
65               int x,y,z;
66               scanf("%d%d%d",&x,&y,&z);
67               addedge(x,y,z);
68           }
69           cout<<maxflow(1,m)<<endl;
70     }
71     return 0;
72 }