Cod sursa(job #2686484)

Utilizator OffuruAndrei Rozmarin Offuru Data 19 decembrie 2020 11:13:43
Problema Arbore partial de cost minim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.66 kb
#include <bits/stdc++.h>

using namespace std;

const int NMAX=2e5+5,MMAX=4e5+5;
int n,m;
vector<pair<int,int>> tree;

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

struct nod
{
    int parent;
    int depth;
    int cost;
} graph[NMAX];

struct edge
{
    int x,y,cost;
    bool operator<(edge a)
    {
        if(a.cost==cost)
            return x<a.x;
        return cost<a.cost;
    }
} edges[MMAX];

int findroot(int x)
{
    if(graph[x].parent==0)
        return x;
    int parent=findroot(graph[x].parent);
    graph[x].parent=parent;
    return parent;
}

void read()
{
    fin>>n>>m;
    for(int i=0; i<m; i++)
        fin>>edges[i].x>>edges[i].y>>edges[i].cost;
    sort(edges,edges+m);
}

void reunion(int r1,int r2,int i)
{
    if(graph[r1].depth==graph[r2].depth)
    {
        graph[r1].cost+=graph[r2].cost+edges[i].cost;
        graph[r2].parent=r1;
        graph[r1].depth++;
    }
    else if(graph[r1].depth>graph[r2].depth)
    {
        graph[r1].cost+=graph[r2].cost+edges[i].cost;
        graph[r2].parent=r1;
    }
    else
    {
        graph[r2].cost+=graph[r1].cost+edges[i].cost;
        graph[r1].parent=r2;
    }
}

void Kruskal()
{
    for(int i=0; i<m; i++)
    {
        int r1=findroot(edges[i].x),r2=findroot(edges[i].y);

        if(r1!=r2)
        {
            reunion(r1,r2,i);
            tree.emplace_back(edges[i].x,edges[i].y);
        }
    }
}

void print()
{
    fout<<graph[findroot(1)].cost<<"\n"<<n-1<<"\n";
    for(auto it: tree)
        fout<<it.first<<" "<<it.second<<"\n";
}

int main()
{
    read();
    Kruskal();
    print();
    return 0;
}