Cod sursa(job #2148299)

Utilizator cezinatorCezar D cezinator Data 1 martie 2018 17:20:35
Problema BFS - Parcurgere in latime Scor 20
Compilator cpp Status done
Runda Arhiva educationala Marime 0.89 kb
#include <fstream>
#include <set>
#include <queue>
#include <iostream>
#include <cmath>
using namespace std;
ifstream fin("bfs.in");
ofstream fout("bfs.out");
set <int> v[100005];
queue <int> q;
int N,M,S,x,y,viz[100005],nivel[100005],p;
void BFS(int i)
{
    viz[i]=1;
    nivel[i]=0;
    q.push(i);
    while(!q.empty())
    {
        p=q.back();
        for(set<int>::iterator it=v[p].begin();it!=v[p].end();it++)
        {
            if(!viz[*it])
            {
                viz[*it]=1;
                q.push(*it);
                nivel[*it]=nivel[p]+1;
            }
        }
        q.pop();
    }
}
int main()
{
    fin>>N>>M>>S;
    for(int i=1;i<=M;i++)
    {
        fin>>x>>y;
        v[x].insert(y);
    }
    BFS(S);
    for(int i=1;i<=N;i++)
    {
        if(!viz[i]) fout<<"-1"<<' ';
        else fout<<nivel[i]<<' ';
    }
    return 0;
}