Cod sursa(job #1669498)

Utilizator CodinPacuraruPacuraru Codin Iosif CodinPacuraru Data 30 martie 2016 19:30:59
Problema Arbore partial de cost minim Scor 50
Compilator cpp Status done
Runda Arhiva educationala Marime 1.72 kb
#include <fstream>
#define NMAX 1800
#define INFINIT 999999999
using namespace std;
ifstream fin("apm.in");
ofstream fout("apm.out");
struct vf
{
    int ext;
    double c;
}g[NMAX][NMAX];
int d[NMAX],n,m,start=1,cmin[NMAX],pre[NMAX],sel[NMAX],cost;
void citire();
void initializare();
void prim();
void afisare();
int main()
{
    citire();
    initializare();
    prim();
    afisare();
    fin.close();
    fout.close();
    return 0;
}
void citire()
{
    int x,y,c,i;
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y>>c;
        ++d[x]; ++d[y];
        g[x][d[x]].ext=y;
        g[x][d[x]].c=c;
        g[y][d[y]].ext=x;
        g[y][d[y]].c=c;
    }
}
void initializare()
{
    int i;
    for(i=1;i<=n;i++)
    {
        cmin[i]=INFINIT;
        pre[i]=start;
    }
    cmin[start]=pre[start]=0;
    for(i=1;i<=d[start];i++)
        cmin[g[start][i].ext]=g[start][i].c;
    sel[start]=1;
}
void prim()
{
    int nr=n-1,vfmin,i,minim;
    while(nr>0)
    {
        minim=INFINIT;
        for(i=1;i<=n;i++)
        {
            if(cmin[i]<minim && !sel[i])
            {
                minim=cmin[i];
                vfmin=i;
            }
        }
        sel[vfmin]=1;
        --nr;
        for(i=1;i<=d[vfmin];i++)
        {
            if(g[vfmin][i].c<cmin[g[vfmin][i].ext] && !sel[g[vfmin][i].ext])
            {
                cmin[g[vfmin][i].ext]=g[vfmin][i].c;
                pre[g[vfmin][i].ext]=vfmin;
            }
        }
    }
}
void afisare ()
{
    int i;
    for (i=1;i<=n;i++)
        cost+=cmin[i];
    fout<<cost<<'\n'<<n-1<<'\n';
    for(i=1;i<=n;i++)
    {
        if(i!=start)
            fout<<pre[i]<<' '<<i<<'\n';
    }
}