Cod sursa(job #709921)

Utilizator adrian_manducadrian manduc adrian_manduc Data 8 martie 2012 18:24:38
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.87 kb
#include <fstream>
#include <iostream>
#include<vector>
#include<queue>
using namespace std;
ifstream f("bfs.in");
ofstream g("bfs.out");
const int N=100099;
vector <int> a[N];
queue <int> q;
int n,v[N],s;
void citire()
{
    int m,x,y;
    f>>n>>m>>s;
    for(int i=1; i<=m; ++i)
    {
      f>>x>>y;
      a[x].push_back(y);
    }
    for(int i=1; i<=n; ++i)
        v[i]=-1;
}
void bfs(int s)
{
   int x,y;
   v[s]=0;
   q.push(s);
   while(!q.empty())
   {
       x=q.front();
       q.pop();
       for( size_t i=0; i<a[x].size(); ++i)
       {
           y=a[x][i];
           if ( v[y]==-1)
           {
               q.push(y);
               v[y]=1+v[x];
           }
       }
   }
}
void afisare()
{
    for(int i=1; i<=n; ++i)
        g<<v[i]<<" ";
}
int main()
{
    citire();
    bfs(s);
    afisare();
    return 0;
}