Cod sursa(job #2342361)

Utilizator vladsftVlad Safta vladsft Data 12 februarie 2019 19:17:25
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.37 kb
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

ifstream in("dijkstra.in");
ofstream out("dijkstra.out");

const int N = 50001;
//vector <int> a[N];
vector <pair<int, int> > a[N];
priority_queue <pair<long long, long long> > h;
int d[N];
bool selectat[N];
const int INF = (1 << 30);
int n;

void citire()
{
    int m, x, y, c;
    in >> n >> m;
    for (int i = 0; i < m; i++)
    {
        in >> x >> y >> c;
        a[x].push_back(make_pair(y, c));
    }
    in.close();
}
void dijkstra(int x0)
{
    int x, y, c;
    pair <int,int> p;
    for (int i = 1; i <= n; i++)
    {
        d[i] = INF;
    }
    d[x0] = 0;
    h.push(make_pair(-d[x0], x0));
    while (!h.empty())
    {
        while (!h.empty() && selectat[h.top().second])
        {
            h.pop();
        }
        if (h.empty())
            return;
        x = h.top().second;
        h.pop();
        selectat[x] = true;
        for (unsigned int i = 0; i < a[x].size(); i++)
        {
            y = a[x][i].first;
            c = a[x][i].second;
            if (d[x] + c < d[y])
            {
                d[y] = d[x] + c;
                h.push(make_pair(-d[y], y));
            }
        }
    }
}
int main()
{
    citire();
    dijkstra(1);
    for (int i = 2; i <= n; i++)
    {
        if (d[i] == INF)
            out << 0 << ' ';
        else out << d[i] <<' ';
    }
    return 0;
}