Cod sursa(job #1101486)

Utilizator goalexboxerFMI Alexandru Ionascu goalexboxer Data 8 februarie 2014 15:51:26
Problema BFS - Parcurgere in latime Scor 20
Compilator cpp Status done
Runda Arhiva educationala Marime 1.19 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];
bool v[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);
    v[nod] = true;

    while( !Q.empty() )
    {
        v[Q.front()] = true;
        for(int i=0,length = G[Q.front()].size();i<length;i++)
        {
            if( v[ G[Q.front()][i] ] != true)
            {
                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++)
    {
        if(i == s)
        {
            g<<0<<" ";
        }
        else if(depth[i] == 0)
        {
            g<<-1<<" ";
        }
        else
         g<<depth[i]<<" ";
    }

    return 0;
}

int main()
{
    read();
    bfs(s);
    write();

    return 0;
}