Cod sursa(job #2438822)

Utilizator oaspruOctavian Aspru oaspru Data 14 iulie 2019 00:14:13
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.1 kb
#include <cstdio>
 
const int maxn = 100001;
 
FILE *in = fopen("bfs.in","r"), *out = fopen("bfs.out","w");
 
struct graf
{
    int nod;
 
    graf *next;
};
 
int n, m, s;
graf *a[maxn];
int v[maxn], c[maxn];
 
void add(int what, int where)
{
    graf *q = new graf;
 
    q->nod = what;
    q->next = a[where];
    a[where] = q;
}
 
void read()
{
    fscanf(in, "%d %d %d", &n, &m, &s);
 
    int x, y;
 
    for ( int i = 0; i < m; ++i )
    {
        fscanf(in, "%d %d", &x, &y);
 
        add(y, x);
    }
}
 
void bfs()
{
    for ( int i = 1; i <= n; ++i )
        v[i] = -1;
 
    v[s] = 0;
 
    int p = 0, u = 0;
    c[p] = s;
 
    while ( p <= u )
    {
        int x = c[p++];
 
        graf *q = a[x];
 
        while ( q )
        {
            if ( v[q->nod] == -1 )
            {
                v[q->nod] = v[x] + 1;
                c[++u] = q->nod;
            }
 
            q = q->next;
        }
    }
 
    for ( int i = 1; i <= n; ++i )
        fprintf(out, "%d ", v[i]);
}
 
int main()
{
    read();
    bfs();
 
    return 0;
}