网络流--最大流ek模板

标准大白书式模板，代码简单但由于效率并不高，所以并不常用，就是这样

 1 #include<stdio.h>
 2 #include<string.h>
 3 #include<queue>
 4 #include<vector>
 5 #include<algorithm>
 6 using namespace std;
 7 const int maxm=150+5;
 8 const int INF=0x3f3f3f3f;
 9
10 struct edge{
11     int from,to,c,f;
12     edge(int a,int b,int m,int n):from(a),to(b),c(m),f(n){}
13 };
14
15 struct ek{
16     int n,m;
17     vector<edge>e;
18     vector<int>g[maxm];
19     int a[maxm];
20     int p[maxm];
21
22     void init(int n){
23         for(int i=0;i<n+3;i++)g[i].clear();
24         e.clear();
25     }
26
27     void add(int from,int to,int c){
28         e.push_back(edge(from,to,c,0));
29         e.push_back(edge(to,from,0,0));
30         m=e.size();
31         g[from].push_back(m-2);
32         g[to].push_back(m-1);
33     }
34
35     int mf(int s,int t){
36         int f=0;
37         while(1){
38             memset(a,0,sizeof(a));
39             queue<int>q;
40             q.push(s);
41             a[s]=INF;
42             while(!q.empty()){
43                 int u=q.front();
44                 q.pop();
45                 for(int i=0;i<g[u].size();i++){
46                     edge tmp=e[g[u][i]];
47                     if(!a[tmp.to]&&tmp.c>tmp.f){
48                         p[tmp.to]=g[u][i];
49                         a[tmp.to]=min(a[u],tmp.c-tmp.f);
50                         q.push(tmp.to);
51                     }
52                 }
53                 if(a[t])break;
54             }
55             if(!a[t])break;
56             for(int i=t;i!=s;i=e[p[i]].from){
57                 e[p[i]].f+=a[t];
58                 e[p[i]^1].f-=a[t];
59
60             }
61             f+=a[t];
62         }
63         return f;
64     }
65 };