Cod sursa(job #1134697)

Utilizator RadEmanuelRad Emanuel RadEmanuel Data 6 martie 2014 20:35:25
Problema Flux maxim Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.78 kb
#include<fstream>
#include<vector>
#include<list>
#include<cstring>
#include<algorithm>
#define DMAX 100
#define INF 21000000
using namespace std;

ifstream fin ("maxflow.in");
ofstream fout("maxflow.out");
list<int> lista;
list<int>::iterator it;
vector< list<int> >l(DMAX,lista);
int n,m,i,x,y,c,fmin,flux,nod;
int cap[DMAX][DMAX],flx[DMAX][DMAX],viz[DMAX],que[DMAX],dad[DMAX];

int bf()
{
    int ls=0,ld=0,nod;
    memset(viz,0,sizeof(viz));
    memset(dad,0,sizeof(dad));
    que[0]=1; viz[1]=1;
    while(ls<=ld)
    {
        nod=que[ls++];
        for(it=l[nod].begin();it!=l[nod].end();++it)
            if(cap[nod][*it]>flx[nod][*it] && !viz[*it])
            {
                if(*it==n)
                {
                    viz[n]=1;
                    continue;
                }
                viz[*it]=1;
                que[++ld]=*it;
                dad[*it]=nod;
            }
    }
    return viz[n];
}

int main()
{
    fin>>n>>m;
    for(i=0;i<m;++i)
    {
        fin>>x>>y>>c;
        l[x].push_back(y);
        l[y].push_back(x);
        cap[x][y]=c;
    }
    while(bf())
    {
        for(it=l[n].begin();it!=l[n].end();++it)
        {
            nod=*it;
            if(cap[nod][n]<=flx[nod][n] || !viz[nod])
                continue;
            dad[n]=nod;
            fmin=INF;
            for(i=n;i!=1;i=dad[i])
                if(fmin>cap[dad[i]][i]-flx[dad[i]][i])
                    fmin=cap[dad[i]][i]-flx[dad[i]][i];
            if(fmin)
            {
                for(i=n;i!=1;i=dad[i])
                {
                    flx[dad[i]][i]+=fmin;
                    flx[i][dad[i]]-=fmin;
                }
                flux+=fmin;
            }
        }
    }
    fout<<flux;
    return 0;
}