Cod sursa(job #1604755)

Utilizator tudormaximTudor Maxim tudormaxim Data 18 februarie 2016 15:47:04
Problema Arbore partial de cost minim Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.33 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;

ifstream fin ("apm.in");
ofstream fout ("apm.out");

const int nmax = 200005;
vector <pair <int,int> > arb;
struct muchie {int x, y, c;} g[nmax];
int dad[nmax], rang[nmax], cmin, n, m;

inline bool cmp(const muchie &a, const muchie &b)
{
    return a.c < b.c;
}

int Find(int x)
{
    while(dad[x]!=x)
        x=dad[x];
    return x;
}

void Union(int x, int y)
{
    if(rang[x] > rang[y]) dad[y]=x;
    else dad[x]=y;
    if(rang[x]==rang[y]) rang[y]++;
}

void Kruskal()
{
    int rx, ry, i;
    for(i=1; i<=n; i++)
        dad[i]=i;
    sort(g+1, g+m+1, cmp);
    for(i=1; i<=m; i++)
    {
        rx=Find(g[i].x);
        ry=Find(g[i].y);
        if(rx!=ry)
        {
            cmin=cmin+g[i].c;
            arb.push_back(make_pair(g[i].x, g[i].y));
            Union(rx, ry);
        }
    }
}

int main()
{
    ios_base::sync_with_stdio(false);
    vector <pair<int,int> > :: iterator it;
    fin >> n >> m;
    for(int i=1; i<=m; i++)
        fin >> g[i].x >> g[i].y >> g[i].c;
    Kruskal();
    fout << cmin << "\n" << n-1 << '\n';
    for(it=arb.begin(); it!=arb.end(); it++)
        fout << it->first << " " << it->second << "\n";
    fin.close();
    fout.close();
    return 0;
}