Cod sursa(job #641064)

Utilizator andrei.finaruFinaru Andrei Emanuel andrei.finaru Data 27 noiembrie 2011 10:24:43
Problema Flux maxim Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.55 kb
#include<fstream>
#include<vector>
#include<queue>
#include<cstring>

using namespace std;

int i,j,n,m,c[1001][1001],flux[1001][1001],x,y,tata[1001],minim,flux_maxim;
vector<int> lista[1001];
queue<int> coada;
int viz[1001];

ifstream f("maxflow.in");
ofstream g("maxflow.out");


int bf()
{
   memset(viz,0,sizeof(viz));
   memset(tata,0,sizeof(tata));

	int x,i,nr_vecini,vecin;
	coada.push(1);
   // g<<1<<' ';
	while(!coada.empty())
	{
		x=coada.front(); coada.pop();
		nr_vecini=lista[x].size();
		for(i=0;i<nr_vecini;i++)
		{
		    vecin=lista[x][i];
			if(!viz[vecin]&&flux[x][vecin]<c[x][vecin])
			{
				viz[vecin]=1;
				tata[vecin]=x;
				coada.push(vecin);
				//g<<vecin<<' ';
			}
		}
	}
	//g<<" sfarsit_coada\n";
 return viz[n];
}


int main()
{
	f>>n>>m;
	for(i=1;i<=m;i++)
	{
		f>>x>>y>>j;
		lista[x].push_back(y);
		lista[y].push_back(x);
		c[x][y]=j;
	}

	while(bf())
	{
		for(i=1;i<n;i++)
			if(tata[i] && flux[i][n]<c[i][n])
			{
				minim=c[i][n]-flux[i][n];
				for(j=i;j!=1;j=tata[j])
					if(c[tata[j]][j]-flux[tata[j]][j]<minim)
						minim=c[tata[j]][j]-flux[tata[j]][j];

                if(minim)
					{
						flux[i][n]=flux[i][n]+ minim;
						flux[n][i]=flux[n][i]- minim;

						for(j=i;j!=1;j=tata[j])
						{
							flux[tata[j]][j]=flux[tata[j]][j]+ minim;
							flux[j][tata[j]]=flux[j][tata[j]]-minim;
						}
						//g<<" adaug la flux "<<minim<<'\n';
						flux_maxim=flux_maxim+minim;
					}
			}
	}
	g<<flux_maxim<<'\n';
	f.close();g.close();
	return 0;
}