Cod sursa(job #936734)

Utilizator BeniaminMarcu Beniamin Beniamin Data 8 aprilie 2013 16:16:50
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.42 kb
#include <cstdio>
#include <vector>
#include <queue>

#define NMAX 50001
#define INF (1 << 30)

using namespace std;

int n;
int d[NMAX];

struct cmp
{
    bool operator () (const int a, const int b) const
    {
        return d[a] > d[b];
    }
};

vector < pair < int, int > > vecin[NMAX];
priority_queue < int, vector < int >, cmp > Q;

void citire()
{
    int m, x, y, c;

    freopen("dijkstra.in", "r", stdin);

    scanf("%d %d", &n, &m);

    while(m --)
    {
        scanf("%d %d %d", &x, &y, &c);

        vecin[x].push_back(make_pair(y, c));
    }
}

void dijkstra(int start)
{
    Q.push(start);
    for(int i = 1; i <= n; d[i ++] = INF);
    d[start] = 0;

    while(!Q.empty())
    {
        int x = Q.top();
        Q.pop();

        unsigned int m = vecin[x].size();
        for(unsigned int i = 0; i < m; ++ i)
        {
            int y = vecin[x][i].first;
            int cost = vecin[x][i].second;

            if(d[y] > d[x] + cost)
            {
                d[y] = d[x] + cost;
                Q.push(y);
            }
        }
    }
}

void afisare_distante()
{
    freopen("dijkstra.out", "w", stdout);

    for(int i = 2; i <= n; ++ i)
        if(d[i] == INF)
            printf("0 ");
        else
            printf("%d ", d[i]);

    printf("\n");
}

int main()
{
    citire();
    dijkstra(1);
    afisare_distante();

    return 0;
}