Cod sursa(job #2468537)

Utilizator ionicaion ionica Data 5 octombrie 2019 16:50:28
Problema Arbore partial de cost minim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.62 kb
#include<fstream>
#include <bits/stdc++.h>
#include<vector>
#include<queue>
#define NM 200001
#define INF 2000000001
#include<stdio.h>

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

int n, m, d[NM],viz[NM],t[NM];
long long ct;
struct  pereche
{
    int y,c;
};

struct compar
{
    bool operator()(pereche p1,pereche p2)
    {
        return p1.c>p2.c;
    }
};

vector<pereche> G[NM];

priority_queue <pereche, vector<pereche>, compar> q;

void Citeste()
{
    int i, x,y;
    pereche u;
    f>>n>>m;
    //fscanf(f,"%d %d",&n,&m);
    for (i=1; i<=m; i++)
    {
        f>>x>>y>>u.c;
        //fscanf(f,"%d %d %d",&x,&u.y,&u.c);
        u.y=y;
        G[x].push_back(u);

        u.y=x;
        G[y].push_back(u);

    }

}
void Prim()
{
    int z,lg,i,nr=0;
    d[1]=0;
    for (i=2; i<=n; i++)
        d[i]=INF;



    pereche p;
    p.y=1;
    p.c=0;
    q.push(p);
    while (!q.empty())
    {

        int j,im,y,c;
        p=q.top();
        q.pop();

        im=p.y;

        if(viz[im])
                continue;

        nr++;
        viz[im]=1;


        ct=ct+d[im];

        for(j=0; j<G[im].size(); j++)
        {
            y=G[im][j].y;
            c=G[im][j].c;

            if(!viz[y] && c<=d[y])
            {
                t[y]=im;
                d[y]=c;
                q.push(G[im][j]);
            }
        }
    }


}
void Scrie()
{
    int i;
    g<<ct<<'\n'<<n-1<<'\n';
    for (i=2; i<=n; i++)
        g<<i<<' '<<t[i]<<'\n';
}
int main()
{
    Citeste();
    Prim();
    Scrie();
    return 0;
}