Cod sursa(job #1242567)

Utilizator bogdanboboc97Bogdan Boboc bogdanboboc97 Data 14 octombrie 2014 18:07:51
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.82 kb
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

ifstream cin("bfs.in");
ofstream cout("bfs.out");

vector< vector<int> > a;
queue<int> q;
int v[100001];
int n,m;

void bfs(int x)
{
    int k;
    q.push(x);
    while(!q.empty())
    {
        k=q.front();q.pop();
        for(vector<int>::iterator i=a[k].begin();i!=a[k].end();++i)
        if(v[*i]==0 && *i!=x && *i!=k)
        {
            q.push(*i);
            v[*i]=v[k]+1;
        }
    }

}

int main()
{
    int i,st,x,y,k;
    cin>>n>>m>>st;
    a=vector< vector<int> >(n+1);
    for(;m;m--)
    {
        cin>>x>>y;
        a[x].push_back(y);
    }
    bfs(st);
    for(i=1;i<=n;i++)
        if(v[i])cout<<v[i]<<' ';
        else if(v[i]==0)
        {
            if(i==st)cout<<0<<' ';
            else cout<<-1<<' ';
        }
    return 0;
}