Cod sursa(job #780753)

Utilizator my666013Test Here my666013 Data 21 august 2012 11:19:44
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.85 kb
#include <cstdio>
#include <vector>
using namespace std;
#define Max 100001

vector<int>g[Max];
int n,m,s,d[Max],c[Max];
bool was[Max];

void bfs(){
    int p,u,x,y;
    c[p = u = 1] = s;
    d[s] = 0;
    was[s] = 1;

    while(p <= u)
    {
        x = c[p++];
        for(int i=0;i<g[x].size();i++)
        {
            y = g[x][i];
            if( !was[y] )
            {
                d[y] = d[x] + 1;
                was[y] = 1;
                c[++u] = y;
            }
        }
    }

}

int main(){
    int a,b;
    freopen("bfs.in","r",stdin);
    freopen("bfs.out","w",stdout);

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

    for(int i=1;i<=m;i++)
    {
        scanf("%d %d",&a,&b);
        g[a].push_back(b);
    }

    bfs();

    for(int i=1;i<=n;i++)
    if(i == s)printf("0 "); else
    if(d[i] == 0)printf("-1 ");else printf("%d ",d[i]);

    return 0;
}