Cod sursa(job #2684910)

Utilizator Giulian617Buzatu Giulian Giulian617 Data 15 decembrie 2020 10:19:37
Problema Arbore partial de cost minim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.41 kb
#include <bits/stdc++.h>
using namespace std;
ifstream f("apm.in");
ofstream g("apm.out");
const int NMAX=200005,INF=0x3F3F3F3F;
int n,m,x,y,price,cost[NMAX];
vector<pair<int,int>>edge[NMAX];
bitset<NMAX>ok;
struct stalker
{
    int a,b;
} solution[NMAX];
void prim(int n)
{
    int mn,node,k=0;
    long long answer=0;
    priority_queue<pair<int,pair<int,int>>,vector<pair<int,pair<int,int>>>,greater<pair<int,pair<int,int>>>>pq;
    ok[1]=1;
    for(int i=1; i<=n; i++)
        cost[i]=INF;
    for(auto next: edge[1])
    {
        cost[next.first]=next.second;
        pq.push({next.second,{next.first,1}});
    }
    for(int i=1; i<=n-1; i++)
    {
        while(ok[pq.top().second.first]==1)
            pq.pop();
        mn=pq.top().first;
        node=pq.top().second.first;
        answer+=mn;
        solution[++k].a=node;
        solution[k].b=pq.top().second.second;
        ok[node]=1;
        for(auto next:edge[node])
        {
            cost[next.first]=min(cost[next.first],next.second);
            pq.push({next.second,{next.first,node}});
        }
    }
    g<<answer<<"\n"<<n-1<<"\n";
    for(int i=1; i<=k; i++)
        g<<solution[i].a<<" "<<solution[i].b<<"\n";
}
int main()
{
    f>>n>>m;
    for(int i=0; i<=m; i++)
    {
        f>>x>>y>>price;
        edge[x].push_back({y,price});
        edge[y].push_back({x,price});
    }
    prim(n);
    return 0;
}