杭电1532----Drainage Ditches『最大流』

 /*
 网络流的最大流问题
 刚学习Dinic算法。模版题
  */
 #include <cstring>
 #include <cstdio>
 #include <queue>
 using namespace std;
 const int maxn = ;
 const int inf = 0x3f3f3f3f;
 struct
 {
     int c,f;
 }edge[maxn][maxn];
 int dis[maxn];
 int v,e;
 bool bfs()
 {
     memset(dis,,sizeof dis);
     queue<int> q;
     q.push();
     dis[] = ;
     while(!q.empty())
     {
         int u = q.front(); q.pop();
         for(int i = ; i <= v; ++i)
             if(!dis[i] && edge[u][i].c > edge[u][i].f)
             {dis[i] = dis[u] + ;q.push(i);}
     }
     return dis[v] != ;
 }
 int dfs(int u,int c)
 {
     if(u == v) return c;
     int temp = c;
     for(int i = ; i <= v && temp; ++i)
     {
         if(dis[i] != dis[u] +  || edge[u][i].c <= edge[u][i].f) continue;
         int t = dfs(i,min(temp,edge[u][i].c - edge[u][i].f));
         edge[u][i].f += t; edge[i][u].f -= t; temp -= t;
     }
     return c - temp;
 }
 int dinic()
 {
     int ans = ;
     while(bfs())
         while(int t = dfs(,inf))
             ans += t;
     return ans;
 }
 int main()
 {
     while(~scanf("%d%d",&e,&v))
     {
         memset(edge,,sizeof edge);
         while(e--)
         {
             int x,y,z;
             scanf("%d%d%d",&x,&y,&z);
             edge[x][y].c += z;
         }
         int ans = dinic();
         printf("%d\n",ans);
     }
     return ;
 }