Cod sursa(job #2692295)

Utilizator MateGMGozner Mate MateGM Data 2 ianuarie 2021 10:15:01
Problema Arbore partial de cost minim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.7 kb
#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
ifstream be("apm.in");
ofstream ki("apm.out");

const int NMAX=200000;

int findset(int i,vector<int>&parent)
{
    if(i==parent[i])
        return i;
    else{
        int root=findset(parent[i],parent);
        parent[i]=root;
        return root;
    }

}

void unionset(int x,int y,vector<int>&parent,vector<int>&rank)
{
    int rx=findset(x,parent);
    int ry=findset(y,parent);
    if(rank[rx]<rank[ry])
        parent[rx]=ry;
    else if(rank[rx]==rank[ry]){
        rank[ry]++;
        parent[rx]=ry;
    }
    else parent[ry]=rx;



}

void kruskal(vector<pair<int,pair<int,int> > >&adj,vector<pair<int,int> >&t,vector<int>&parent,vector<int>&rank,int &db,int &m,int &k)
{
    int xRep,yRep;
    sort(adj.begin(),adj.end());
    for(int i=0;i<m;i++)
    {
        xRep=findset(adj[i].second.first,parent);
        yRep=findset(adj[i].second.second,parent);
        if(xRep!=yRep)
        {
            t[k++] = {adj[i].second.first,adj[i].second.second};
            db+=adj[i].first;
            unionset(xRep,yRep,parent,rank);
        }
    }

}

int main()
{
    int n,m,db=0,k=0;
    be>>n>>m;
    vector<pair<int,pair<int,int> > >adj;
    for(int i=0;i<m;i++)
    {
        int x,y,c;
        be>>x>>y>>c;
        adj.push_back({c,{x,y}});
    }
    vector<int>parent(n+1);
    vector<int>rank(n+1,0);
    for(int i=1;i<=n;i++)
        parent[i]=i;
    vector<pair<int,int> >t(NMAX);
    kruskal(adj,t,parent,rank,db,m,k);
    ki<<db<<endl;
    ki<<k<<endl;
    for(int i=0;i<k;i++)
    {
        ki<<t[i].second<<" "<<t[i].first<<endl;
    }

    return 0;
}