Cod sursa(job #1112607)

Utilizator teo.serbanescuTeo Serbanescu teo.serbanescu Data 19 februarie 2014 21:25:44
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.13 kb
#include <fstream>
#include <vector>
#include <queue>
#include <string.h>

using namespace std;

fstream f("bfs.in",ios::in);
fstream g("bfs.out",ios::out);

const int nmax=100005,INF=0x3f3f3f3f;

vector <int> a[nmax];
queue <int> q;

int n,m,s,i,x,y,nc,dist[nmax],viz[nmax];

void citire()
{
    f>>n>>m>>s;
    for (i=1;i<=m;i++)
    {
        f>>x>>y;
        a[x].push_back(y);
    }
}

void rezolvare()
{
    memset (dist,INF,sizeof(dist));
    memset(viz,0,sizeof(viz));
    viz[s]=1;
    dist[s]=0;
    q.push(s);
    while (!q.empty())
    {
        nc=q.front();
        q.pop();
        for (vector<int>::iterator it=a[nc].begin();it!=a[nc].end();++it)
            if (dist[nc]+1<dist[*it])
            {
                dist[*it]=dist[nc]+1;
                if (!viz[*it])
                {
                    q.push(*it);
                    viz[*it]=1;
                }
            }

    }
}

void afisare()
{
    for (i=1;i<=n;i++) g<<((dist[i]<INF)?dist[i]:-1)<<" ";
}

int main()
{
    citire();
    rezolvare();
    afisare();
    f.close();g.close();
    return 0;
}