1459 poj

 

很裸的网络流 加一个汇点 和原点就行了

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;

const int MAXN = 20000;

const int inf = 0x7fffffff;

const int s = 0;

struct edge{
       int v,next,w;
}edge[1000000];

int head[2*MAXN],cnt;//for sap

void addedge(int u, int v, int w)
{
     edge[cnt].v = v;
     edge[cnt].w = w;
     edge[cnt].next = head[u];
     head[u] = cnt++;
     edge[cnt].v = u;
     edge[cnt].w = 0;
     edge[cnt].next = head[v];
     head[v] = cnt++;
}

int sap(int t)
{
    //cout << " sap " << endl;
    int pre[2*MAXN],cur[2*MAXN],dis[2*MAXN],gap[2*MAXN]; //gap±ê¼Ç¶Ï²ã
    int flow = 0 , aug = inf ,u;
    bool flag;
    for (int i = 0 ; i <= t ; ++i)
    {
        cur[i] = head[i];
        gap[i] = dis[i] = 0;
    }
    gap[s] = t+1;
    u = pre[s] = s;
    while (dis[s] <= t)
    {
          flag = 0 ;
          for (int &j = cur[u] ; ~j ; j = edge[j].next)
          {
              int v = edge[j].v;
              if (edge[j].w > 0 && dis[u] == dis[v]+1)
              {
                   flag = 1;
                   if( edge[j].w < aug )aug = edge[j].w;
                   pre[v] = u;
                   u = v;
                   if (u == t)
                   {
                       flow += aug;
                       while (u != s)
                       {
                             u = pre[u];
                             edge[cur[u]].w -= aug;
                             edge[cur[u]^1].w += aug;
                       }
                       aug = inf;
                   }
                   break;
              }
          }
          if ( flag )continue ;
          int mindis = t+1;
          for (int j = head[u]; ~j ; j = edge[j].next)
          {
              int v = edge[j].v;
              if (edge[j].w > 0 && dis[v] < mindis)
              {
                 mindis = dis[v];
                 cur[u] = j;
              }
          }
          if(--gap[dis[u]] == 0)break;
          gap[ dis[u] = mindis+1 ]++;
          u = pre[u];
    }
    return flow;
}

void init ()
{
     memset (head , -1 , sizeof(head));
     cnt=0;
}

int main()
{
    int n , np , nc , m;
    while (scanf("%d%d%d%d" , &n , &np , &nc , &m )!= EOF )
    {
        int a, b , c;
        init ();
        for ( int i = 0 ; i < m ; i ++ )
        {

            scanf(" (%d,%d)%d" , &a, &b, &c );
            a++, b++;
            //cout << a << " **** " <<b <<  endl;
            addedge (a, b , c);
        }
        //cout <<" here" << endl;
        for ( int i = 0 ; i < np ; i ++ )
        {
            scanf(" (%d)%d" , &a, &c );
            a++;
            //cout << a <<"***** " <<c << endl;
            addedge ( 0 , a , c );
        }
        //cout << " adfasdf " << endl;
        for ( int i = 0 ; i < nc ; i ++ )
        {
            scanf(" (%d)%d" , &a , &c );
            a++;

            addedge ( a , n+1, c );
        }

        printf("%d\n" , sap ( n+1 ) );
    }
    return 0;
}