Cod sursa(job #871646)

Utilizator TeodoraTanaseTeodora Tanase TeodoraTanase Data 4 februarie 2013 22:54:12
Problema Algoritmul lui Dijkstra Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.46 kb
#include <cstdio>
#include <vector>
#include <queue>

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

using namespace std;

FILE *inFile = fopen("dijkstra.in", "r");
FILE *outFile = fopen("dijkstra.out", "w");

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

void read()
{
    int m;
    int x;
    int y;
    int c;

    fscanf(inFile, "%d %d\n", &n, &m);

    while(m --)
    {
        fscanf(inFile, "%d %d %d\n", &x, &y, &c);
        G[x].push_back(make_pair(y, c));
    }
}

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

    d[v] = 0;

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

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

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

void write()
{
    for(int i = 2; i <= n; ++ i)
        if (d[i] == INF)
            fprintf (inFile, "0 ");
        else
            fprintf (inFile, "%d ", d[i]);

    fprintf (inFile, "\n");
}

int main()
{
    read();
    dijkstra(1);
    write();

    return 0;
}