1 #include<cstdio> 2 #include<cstring> 3 #include<algorithm> 4 #include<queue> 5 using namespace std; 6 #define INF 2147483647 7 #define MAXN 201 8 #define MAXM 1501 9 int v[MAXM],cap[MAXM],en,first[MAXN],next[MAXM]; 10 int d[MAXN],cur[MAXN]; 11 queue<int>q; 12 int m,S,T,W; 13 char U[1],V[1]; 14 void Init_Dinic(){memset(first,-1,sizeof(first)); en=0; S='A'; T='Z';} 15 void AddEdge(const int &U,const int &V,const int &W) 16 {v[en]=V; cap[en]=W; next[en]=first[U]; first[U]=en++; 17 v[en]=U; next[en]=first[V]; first[V]=en++;} 18 bool bfs() 19 { 20 memset(d,-1,sizeof(d)); q.push(S); d[S]=0; 21 while(!q.empty()) 22 { 23 int U=q.front(); q.pop(); 24 for(int i=first[U];i!=-1;i=next[i]) 25 if(d[v[i]]==-1 && cap[i]) 26 { 27 d[v[i]]=d[U]+1; 28 q.push(v[i]); 29 } 30 } 31 return d[T]!=-1; 32 } 33 int dfs(int U,int a) 34 { 35 if(U==T || !a) return a; 36 int Flow=0,f; 37 for(int &i=cur[U];i!=-1;i=next[i]) 38 if(d[U]+1==d[v[i]] && (f=dfs(v[i],min(a,cap[i])))) 39 { 40 cap[i]-=f; cap[i^1]+=f; 41 Flow+=f; a-=f; if(!a) break; 42 } 43 if(!Flow) d[U]=-1; 44 return Flow; 45 } 46 int max_flow() 47 { 48 int Flow=0,tmp=0; 49 while(bfs()) 50 { 51 memcpy(cur,first,sizeof(cur)); 52 while(tmp=dfs(S,INF)) Flow+=tmp; 53 } 54 return Flow; 55 } 56 int main() 57 { 58 scanf("%d",&m); Init_Dinic(); 59 for(int i=1;i<=m;++i) 60 { 61 scanf("%s%s%d",U,V,&W); 62 AddEdge(U[0],V[0],W); 63 } 64 printf("%d ",max_flow()); 65 return 0; 66 }