Cod sursa(job #1846885)

Utilizator danyvsDan Castan danyvs Data 14 ianuarie 2017 08:56:12
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.59 kb
#include <fstream>
#include <algorithm>
#include <vector>
#include <queue>

using namespace std;

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

const int NMAX = 50001;

#define INF 0x3f3f3f3f

int n, m;
vector < vector < pair < int, int > > > V(NMAX);
priority_queue < pair < int, int >, vector < pair < int, int > >, greater < pair < int, int > > > PQ;
int D[NMAX];

void read()
{
    int i, x, y, cost;
    fin >> n >> m;
    for (i = 1; i <= m; ++ i)
        {
         fin >> x >> y >> cost;
         V[x].push_back(make_pair(cost, y));
        }
}

void dijkstra(int source)
{
    int v, d, v2, cost, i;
    vector < pair < int, int > > :: iterator it;
    for (i = 1; i <= n; ++ i)
        D[i] = INF;
    D[source] = 0;
    PQ.push(make_pair(0, source));
    while (!PQ.empty())
        {
         d = PQ.top().first;
         v = PQ.top().second;
         PQ.pop();
         if (D[v] == d)
            for (it = V[v].begin(); it != V[v].end(); ++ it)
                {
                 cost = (*it).first;
                 v2 = (*it).second;
                 if (D[v2] > d + cost)
                    {
                     D[v2] = d + cost;
                     PQ.push(make_pair(D[v2], v2));
                    }
                }
        }
}

void print()
{
    int i;
    for (i = 2; i <= n; ++ i)
        if (D[i] != INF)
            fout << D[i] << " ";
        else
            fout << 0 << " ";
    fout << "\n";
}

int main()
{
    read();
    fin.close();
    dijkstra(1);
    print();
    fout.close();
    return 0;
}