Cod sursa(job #2705208)

Utilizator vlad_butnaruVlad Butnaru vlad_butnaru Data 12 februarie 2021 10:01:44
Problema Algoritmul lui Dijkstra Scor 30
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.54 kb
#include <bits/stdc++.h>
using namespace std;
ifstream in ("dijkstra.in");
ofstream out ("dijkstra.out");
vector <pair <int , int > > v[50001];
int N, M;
int dist[50001];
int dad[50001];
void dijkstra (int start)
{
    set <pair <int , int > > seti;
    dist[start] = 0;
    for (int i = 0; i < v[start].size(); ++i)
    {
        pair <int , int> pp = make_pair(v[start][i].second, v[start][i].first);
        seti.insert(pp);
        dad[v[start][i].first] = start;
    }
    while (!seti.empty())
    {
        int cost = (*seti.begin()).first;
        int place = (*seti.begin()).second;
        int tata = dad[place];
        seti.erase(seti.begin());
        if (dist[place] == -1)
        {
           dist[place] = dist[tata] + cost;
           for (int i = 0; i<v[place].size();++i)
           {
                if (dist[v[place][i].first] == -1)
                {
                    dad[v[place][i].first] = place;
                    seti.insert({v[place][i].second,v[place][i].first});
                }
           }
        }
        if (dist[tata] + cost < dist[place])
            dist[place] = dist[tata] + cost;
    }

}
int main ()
{
    in >> N >> M;
    for (int i = 1; i<=M; ++i)
    {
        int a, b, c;
        in >> a >> b >> c;
        v[a].push_back({b,c});
    }
    for (int i = 1;i<=N;++i)
        dist[i] = -1;
    dijkstra(1);
    for (int i = 2; i<=N; ++i)
        if (dist[i] == -1)
            out << 0 << ' ';
        else
            out << dist[i] << ' ';
    return 0;
}