Cod sursa(job #1666685)

Utilizator superstar1998Moldoveanu Vlad superstar1998 Data 28 martie 2016 11:39:45
Problema Flux maxim Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.34 kb
#include <fstream>
#include <vector>
#define NMAX 1001
using namespace std;
int n,m,F[NMAX][NMAX],C[NMAX][NMAX],flux,x,y,r;
int T[NMAX],q[NMAX];
vector<int> G[NMAX];
vector<int>::iterator it;
ifstream f("maxflow.in");
ofstream g("maxflow.out");
int BF()
{
    int i,k,p,u;
    p=u=0;
    for(i=1;i<=n;i++)
        T[i]=0;
    q[0]=1;
    T[1]=-1;
    for(;p<=u;p++)
    {
        k=q[p];
        for(it=G[k].begin();it!=G[k].end();it++)
            if(!T[*it]&&C[k][*it]>F[k][*it])
            {
                q[++u]=*it;
                T[*it]=k;
                if(*it==n)return 1;
            }
    }
    return 0;
}
int main()
{
    f>>n>>m;
    int i,j;
    for(i=1;i<=m;i++)
    {
        f>>x>>y;
        f>>C[x][y];
        G[x].push_back(y);
        G[y].push_back(x);
    }
    while(BF())
        for(it=G[n].begin();it!=G[n].end();it++)
        {
            if(T[*it]==-1||C[*it][n]<=F[*it][n])continue;
            r=C[*it][n]-F[*it][n];
            for(j=*it;j!=1&&j;j=T[j])
                r=min(r,C[T[j]][j]-F[T[j]][j]);
            if(r==0)continue;
            F[*it][n]+=r;
            F[n][*it]-=r;
            for(j=*it;j!=1;j=T[j])
            {
                F[T[j]][j]+=r;
                F[j][T[j]]-=r;
            }
            flux+=r;
        }
    g<<flux;
    return 0;
}