Cod sursa(job #2175737)

Utilizator TudorFinaruTudor Cristian Finaru TudorFinaru Data 16 martie 2018 18:45:59
Problema Arbore partial de cost minim Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.61 kb
#include <fstream>
#include<set>
#include<vector>

using namespace std;
ifstream f("apm.in");
ofstream g("apm.out");

int n,m,r[200003],p[200003],cost,componente;

struct muchie{int x; int y; int c; friend bool operator <(muchie m1, muchie m2){ return(m2.c>m1.c || (m1.c==m2.c && m2.x>m1.x) || (m1.c==m2.c && m2.x==m1.x && m1.y>m2.y));}
};

set<muchie>v;
vector<pair<int, int> > APM;

void make_set()
{
    for(int i=1;i<=n;i++) {
        r[i]=1;
        p[i]=i;
    }
}

int Find(int x)
{
    if(p[x]!=x) p[x]=Find(p[x]);
    return p[x];
}

void Union(int x, int y)
{
    int xroot,yroot;
    xroot=Find(x); yroot=Find(y);
    if(xroot==yroot) return;
    if(r[xroot]<r[yroot])
    {
        r[yroot]+=r[xroot];
        p[xroot]=yroot;
    }
    else
    {
        r[xroot]+=r[yroot];
        p[yroot]=xroot;
    }
    componente--;
}



int main()
{
    componente=n;
    int i,x,y,c;
    muchie aux;
    f>>n>>m;
    for(i=1;i<=m;i++)
    {
        f>>x>>y>>c;
        aux.x=x; aux.y=y; aux.c=c;
        v.insert(aux);
    }
    make_set();
    for(set<muchie>::iterator it=v.begin();it!=v.end();++it)
    {
        x=it->x; y=it->y; c=it->c;
        if(Find(x)!=Find(y))
        {
            Union(x,y);
            cost+=c;
            APM.push_back(make_pair(x,y));
            componente--;
        }
        if(componente==1) break;
    }
    g<<cost<<'\n'<<APM.size()<<'\n';
    vector<pair<int, int> >::iterator it;
    for(it=APM.begin();it!=APM.end();++it)
        g<<it->first<<' '<<it->second<<'\n';
    f.close();
    g.close();
    return 0;
}