Cod sursa(job #1922517)

Utilizator Harsan_SabinHarsan Sabin Harsan_Sabin Data 10 martie 2017 17:46:28
Problema Arbore partial de cost minim Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.48 kb
#include <fstream>
#include <algorithm>

using namespace std;

ifstream cin("apm.in");
ofstream cout("apm.out");

struct co{ int a,b,cost; };

int n,m,i,j,c;

int a[400002];

co Gf[400002];

int Pa[200002],Rk[200002];

int find_p(int x)
{
    if(Pa[x]!=x)
        Pa[x]=find_p(Pa[x]);
    return Pa[x];
}

void Union(int a,int b)
{
    int ix=find_p(a);
    int iy=find_p(b);

    if(Rk[ix]>Rk[iy])
        Pa[iy]=ix;

    if(Rk[ix]<Rk[iy])
        Pa[ix]=iy;

    if(Rk[ix]==Rk[iy])
    {
        Pa[iy]=ix;
        ++Rk[ix];
    }
}

int IsCycle(int a,int b)
{
    int ix=find_p(a);
    int iy=find_p(b);

    if(ix==iy)
        return 1;
    return 0;
}

void Afisare(int nr)
{
    int costa=0;

    for(int k=1;k<=nr;++k)
        costa+=Gf[a[k]].cost;

    cout<<costa<<'\n'<<n-1<<'\n';

    for(int k=1;k<=nr;++k)
        cout<<Gf[a[k]].b<<' '<<Gf[a[k]].a<<'\n';
}

int Kruskal()
{
    int nrm=0;

    for(int k=1;k<=m;++k)
        if(!IsCycle(Gf[k].a,Gf[k].b))
        {
            a[++nrm]=k;
            Union(Gf[k].a,Gf[k].b);
        }

    return nrm;
}

bool Pred(co x, co z)
{
    if(x.cost<z.cost)
        return 1;
    return 0;
}

int main()
{
    cin>>n>>m;

    for(int k=1;k<=m;++k)
    {
        cin>>i>>j>>c;
        Pa[i]=i;
        Pa[j]=j;

        Gf[k].a=i;
        Gf[k].b=j;
        Gf[k].cost=c;
    }

    sort(Gf+1,Gf+m+1,Pred);

    Afisare(Kruskal());

    return 0;
}