Cod sursa(job #2207455)

Utilizator andreichiricaAndrei Chirica andreichirica Data 25 mai 2018 19:01:33
Problema BFS - Parcurgere in latime Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 0.92 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream fin("bfs.in");
ofstream fout("bfs.out");
vector <int> a[100002];
queue <int> q;
int n,m,s,x,y,p[100002],viz[100002];
void bfs(int v)
{

    q.push(v);
    int pas=0;
    viz[v]=1;
    while(!q.empty())
    {
        x=q.back();
        q.pop();
        pas++;
        for(int i=0;i<a[x].size();i++)
        {
            p[a[x][i]]=pas;
            if(viz[a[x][i]]==0)
            q.push(a[x][i]);
            viz[a[x][i]]=1;
        }
    }

}


int main()
{
    fin>>n>>m>>s;
    for(int i=1;i<=m;i++)
    {
        fin>>x>>y;
        a[x].push_back(y);

    }
    bfs(s);
    for(int i=1;i<=n;i++)
    {
        if(i==s)
            fout<<0<<" ";
        else
            if(viz[i]==0)
                fout<<-1<<" ";
        else
            fout<<p[i]<<" ";
    }
    return 0;
}