Cod sursa(job #1882860)

Utilizator trutruvasilicaHuhurez Marius trutruvasilica Data 17 februarie 2017 15:52:24
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.84 kb
#include <fstream>
#include <vector>
#include <queue>
#include <cstring>
using namespace std;
ifstream fin("bfs.in");
ofstream fout("bfs.out");
const int N=100001;
vector<int>H[N];
queue<int>Q;
int dist[N],n,m,i,s,a,b;
void bfs(int start)
{
    dist[start]=1;
    Q.push(start);
    while(Q.size())
    {
        a=Q.front();
        for(vector<int>::iterator it=H[a].begin();it!=H[a].end();it++)
        {
            if(dist[*it]==0||(dist[a]+1<dist[*it]))
            {
                Q.push(*it);
                dist[*it]=dist[a]+1;
            }
        }
        Q.pop();
    }
}
int main()
{
    fin>>n>>m>>s;
    while(m--)
    {
        fin>>a>>b;
        H[a].push_back(b);
    }
    bfs(s);
    for(i=1;i<=n;i++)
    {
        if(dist[i]==0) fout<<"-1 ";
        else fout<<dist[i]-1<<" ";
    }

}