Cod sursa(job #1101508)

Utilizator goalexboxerFMI Alexandru Ionascu goalexboxer Data 8 februarie 2014 16:27:09
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.1 kb
#include<vector>
#include<fstream>
#include<queue>
using namespace std;

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

#define MAXN 100003

vector<int> G[MAXN];
queue<int> Q;
int depth[MAXN];

int n,m,s;
int nr;

int read()
{
    f>>n;
    f>>m;
    f>>s;

    int x,y;

    for(int i=1;i<=m;i++)
    {
        f>>x;
        f>>y;
        G[x].push_back(y);
    }

    return 0;
}

int bfs(int nod)
{
    Q.push(nod);
    depth[nod] = 0;

    while( !Q.empty() )
    {
        for(int i=0,length = G[Q.front()].size();i<length;i++)
        {
            if( depth[ G[Q.front()][i] ] == -1 && depth[ G[Q.front()][i] ] != 0  )
            {
                Q.push( G[Q.front()][i] );
                depth[G[Q.front()][i]] = depth[Q.front()] + 1;
            }
        }


        Q.pop();
    }

    return 0;

}

int write()
{
    for(int i=1;i<=n;i++)
    {
         g<<depth[i]<<" ";
    }

    return 0;
}

int main()
{

    read();

    for(int i=1;i<=n;i++)
    {
        depth[i] = -1;
    }

    bfs(s);
    write();

    return 0;
}