Cod sursa(job #1447887)

Utilizator andreator11ilies andreea andreator11 Data 5 iunie 2015 17:58:42
Problema BFS - Parcurgere in latime Scor 80
Compilator cpp Status done
Runda Arhiva educationala Marime 0.85 kb
#include <fstream>
#include <queue>
#include <set>

using namespace std;
ifstream f("bfs.in");
ofstream g("bfs.out");

queue<int> q;
int n,m,s,fr[100001],i,a,b;
set<int> v[100001];
set<int>::iterator it;

void initializare()
{
    for(i=1;i<=n;i++)
        fr[i]=-1;
        fr[s]=0;
}
void citire()
{
    f>>n>>m>>s;
    q.push(s);
    for(i=1;i<=m;i++)
    {
        f>>a>>b;
        v[a].insert(b);
        //v[b].insert(a);
    }
}
void coada()
{
    int k;
    while(!q.empty())
    {
     k=q.front();
     for (it=v[k].begin(); it!=v[k].end(); it++)
      if(fr[*it]==-1 or fr[*it]>fr[k]+1)
      {q.push(*it);
       fr[*it]=fr[k]+1;}
       q.pop();
    }
}
void afisare()
{
    for (i=1;i<=n;i++)
    g<<fr[i]<<" ";
}
int main()
{
    citire();
    initializare();
    coada();
    afisare();
    return 0;
}