Cod sursa(job #1690534)

Utilizator BugirosRobert Bugiros Data 15 aprilie 2016 11:20:14
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.53 kb
#include <fstream>
#include <queue>
#include <vector>
using namespace std;

const int MAXN = 50005;
const int INF = 1 << 30;

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

vector<int> vecini[MAXN];
vector<int> cost[MAXN];
int n;

int d[MAXN];

struct nod_dijk
{
    int nod,dist;
    bool operator < (const nod_dijk &b) const
    {
        return dist > b.dist;//heap de maxime
    }
};

void citire()
{
    int m;
    in >> n >> m;
    for (int i = 1;i <= m;++i)
    {
        int a,b,c;
        in >> a >> b >> c;
        vecini[a].push_back(b);
        cost[a].push_back(c);
    }
}

priority_queue<nod_dijk> heap;

void dijkstra(int sursa)
{
    for(int i = 1;i <= n;++i)
        d[i] = INF;
    d[sursa] = 0;
    heap.push((nod_dijk){sursa,0});
    while(!heap.empty())
    {
        int nod = heap.top().nod;
        int dist = heap.top().dist;
        heap.pop();
        if (d[nod] != dist)
            continue;
        for (unsigned int i = 0;i < vecini[nod].size();++i)
        {
            int vecin = vecini[nod][i];
            int c = cost[nod][i];
            if (d[nod] + c < d[vecin])
            {
                d[vecin] = d[nod] + c;
                heap.push((nod_dijk){vecin,d[vecin]});
            }
        }
    }
}

void afisare()
{
    for (int i = 2;i <= n;++i)
        if (d[i] == INF)
            out << 0 << ' ';
        else out << d[i] << ' ';
    out << '\n';
}

int main()
{
    citire();
    dijkstra(1);
    afisare();
    return 0;
}