Cod sursa(job #2111466)

Utilizator Fanika123Tanasa Stefan Fanika123 Data 22 ianuarie 2018 10:12:06
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.39 kb
#include <fstream>
#include <vector>
#include <queue>
#include <bitset>
#define inf 1e7
#define in "dijkstra.in"
#define out "dijkstra.out"
using namespace std;
ifstream fin (in);
ofstream fout(out);

int n, dist[50005];
bitset <50005> viz;
vector < pair <int, int> > v[50005];
priority_queue < pair <int, int> > heap;

void Dijkstra()
{
    for(int i = 1; i <= n; ++i) dist[i] = inf;

    dist[1] = 0;

    heap.push(make_pair(0, 1));
    while(!heap.empty())
    {
        int nod = heap.top().second;
        heap.pop();

        if(viz[nod]) continue;
        viz[nod] = 1;
        for(int i = 0; i < v[nod].size(); ++i)
        {
            int p, q;
            p = v[nod][i].first;
            q = v[nod][i].second;
            /// drum de la nodul nod la nodul p cu costul q
            if(dist[p] > dist[nod] + q)
            {
                dist[p] = dist[nod] + q;
                heap.push(make_pair(-dist[p], p)); /// -dist[p] daca e cea mai mica va fi prima in pq, va avea prioritate
            }
        }
    }
}

int main()
{
    int m, x, y, p;
    fin >> n >> m;
    while(m--)
    {
        fin >> x >> y >> p;
        v[x].push_back(make_pair(y, p));
    }
    fin.close();

    Dijkstra();

    for(int i = 2; i <= n; ++i)
        if(dist[i] != inf) fout << dist[i] << " ";
        else fout << "0 ";
    fout.close();
    return 0;
}