Cod sursa(job #477859)

Utilizator APOCALYPTODragos APOCALYPTO Data 16 august 2010 14:31:16
Problema Flux maxim Scor 70
Compilator cpp Status done
Runda Arhiva educationala Marime 2.24 kb
using namespace std;
#include<iostream>
#include<fstream>
#include<vector>
#include<queue>
#include<cstring>
#define Nmax 1105
#define pb push_back
vector<int> G[1005];
ofstream fout("maxflow.out");
int C[1005][1005];
int F[1005][1005];
int viz[1005];
int ante[1005];
int N,M;
queue<int> q;
int dim=8192;
char ax[8192];
int pz;
//ofstream fout("poly.out");
inline void cit(int &x)
{
    x = 0;
    while(ax[pz] < '0' || ax[pz] > '9')
	if(++pz == dim) fread(ax,1, dim, stdin),pz = 0;

    while(ax[pz] >= '0' && ax[pz] <= '9')
    {
	x = x * 10 + ax[pz] - '0';
	if(++pz == dim) fread(ax,1,dim,stdin),pz = 0;
    }
}
int BFS()
{
int qu[1005];
int u,i,V;
    //while(!q.empty())
     //q.pop();
    memset(viz,0,sizeof(viz));
    viz[1]=1;
    //q.push(1);
    qu[0]=1;
    qu[1]=1;
    int alfa=1;

    while(alfa<=qu[0])
    {
        u=qu[alfa];
        //q.pop();
        alfa++;
        //for(it=G[u].begin();it!=G[u].end();++it)
        for(i=0;i<G[u].size();i++)
        { V=G[u][i];
          if(viz[V]==0)
           if(F[u][V]<C[u][V])
            {
                viz[V]=1;
                ante[V]=u;
                qu[0]++;
                qu[qu[0]]=V;

            }
        }


    }
    if(viz[N]==1)
     return 1;
    return 0;

}

void solve()
{int i,flow,fmin,k;

vector<int>::iterator it;
  for(flow=0;BFS();)
  {fmin = 2891821;
    for(it=G[N].begin();it!=G[N].end();it++)
      if(viz[*it]==1&&C[*it][N]>0)
      {fmin = C[*it][N]-F[*it][N];
          for(i=*it;i!=1;i=ante[i])

      fmin=min(fmin,C[ante[i]][i]-F[ante[i]][i]);
                F[*it][N]+=fmin;
          F[N][*it]-=fmin;
      for(i=*it;i!=1;i=ante[i])
      {
          F[ante[i]][i]+=fmin;
          F[i][ante[i]]-=fmin;
      }
      flow+=fmin;
      }

  }
  fout<<flow<<"\n";

}

void cit()
{int x,y,z,i;
    //ifstream fin("maxflow.in");
    //fin>>N>>M;
    cit(N);cit(M);
    for(i=1;i<=M;i++)

     {//fin>>x>>y>>z;
         cit(x);
         cit(y);
         cit(z);
     C[x][y]+=z;
     F[y][z]=0;
     G[x].pb(y);
     G[y].pb(x);
     }
     //fin.close();

}

int main()
{ freopen("maxflow.in","r",stdin);
    cit();
    solve();
    fout.close();
    return 0;
}