Cod sursa(job #144768)

Utilizator DastasIonescu Vlad Dastas Data 27 februarie 2008 22:29:08
Problema Algoritmul lui Dijkstra Scor Ascuns
Compilator cpp Status done
Runda Marime 1.51 kb
#include <cstdio>

const int maxn = 50001;
const int inf = 1 << 30;

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

struct graf
{
    int nod, cost;
    graf *next;
};

int n, m;
graf *a[maxn];

int p, u;
int c1[maxn], c2[maxn], v[maxn];

int d[maxn];

void add(int where, int what, int cost)
{
    graf *q = new graf;
    q->nod = what;
    q->cost = cost;
    q->next = a[where];
    a[where] = q;
}

void read()
{
    fscanf(in, "%d %d", &n, &m);

    int x, y, z;
    for ( int i = 1; i <= m; ++i )
    {
        fscanf(in, "%d %d %d", &x, &y, &z);
        add(x, y, z);
    }
}

void bford()
{
    for ( int i = 2; i <= n; ++i )
        d[i] = inf;

    c1[++p] = 1;
    v[1] = 1;

    while ( p )
    {
        for ( int i = 1; i <= p; ++i )
        {
            graf *q = a[ c1[i] ];
            v[ c1[i] ] = 0;

            while ( q )
            {
                if ( d[ q->nod ] > d[ c1[i] ] + q->cost )
                {
                    d[ q->nod ] = d[ c1[i] ] + q->cost;

                    if ( !v[ q->nod ] )
                        c2[++u] = q->nod, v[ q->nod ] = 1;
                }

                q = q->next;
            }
        }

        p = u;
        for ( int i = 1; i <= u; ++i )
            c1[i] = c2[i];
        u = 0;
    }
}

int main()
{
    read();
    bford();

    for ( int i = 2; i <= n; ++i )
        fprintf(out, "%d ", d[i] == inf ? 0 : d[i]);
    fprintf(out, "\n");


	return 0;
}