Cod sursa(job #1378488)

Utilizator RathebaSerbanescu Andrei Victor Ratheba Data 6 martie 2015 12:31:32
Problema Algoritmul lui Dijkstra Scor 10
Compilator cpp Status done
Runda Arhiva educationala Marime 1.44 kb
#include <cstdio>
#include <algorithm>
#include <vector>

using namespace std;
#define MAX 50005
#define INF 50000005

struct pereche
{
    int nod, cost;
};


vector<pereche> v[MAX];
vector<int> heap;
int n, m, drum[MAX];
void dij(int sursa);
bool comp(int a, int b)
{
    return drum[a] > drum[b];
}


int main()
{
    freopen("dijkstra.in", "r", stdin);
    freopen("dijkstra.out", "w", stdout);
    int i, a, b, c;
    pereche p;
    scanf("%d%d", &n, &m);
    for(i=1; i<=m; i++)
    {
        scanf("%d%d%d", &a, &b, &c);
        p.nod = b; p.cost = c;
        v[a].push_back(p);
    }
    dij(1);
    for(i=2; i<=n; i++)
        printf("%d ", drum[i]);
    return 0;
}
void dij(int sursa)
{
    int i, fiu, tata, cost;
    for(i=1; i<=n; i++)
        drum[i] = INF;
    drum[sursa] = 0;
    heap.push_back(sursa);
    make_heap(heap.begin(), heap.end(), comp);

    vector<pereche>::iterator it;
    while(!heap.empty())
    {
        tata = heap[0];
        pop_heap(heap.begin(), heap.end(), comp);
        heap.pop_back();
        if(drum[tata] == INF) break;
        for(it=v[tata].begin(); it!=v[tata].end(); ++it)
        {
            fiu = it -> nod; cost = it -> cost;
            if(drum[fiu] > drum[tata] + cost){
                drum[fiu] = drum[tata] + cost;
                heap.push_back(fiu);
                push_heap(heap.begin(), heap.end(), comp);
            }
        }
    }
}