Cod sursa(job #1373738)

Utilizator httpsLup Vasile https Data 4 martie 2015 20:21:31
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.81 kb
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

#define foor(it,v) for(it=v.begin();it!=v.end();++it)

int n,m,start,x,y,i;
vector <vector<int> > G;
vector<int> dist;
queue<int> q;

void bfs(int start)
{
    int nod;
    vector<int>::iterator it;

    dist[start]=0;
    q.push(start);
    while(!q.empty())
    {
        nod=q.front();
        q.pop();
        foor(it,G[nod]) if(dist[*it]==-1)
        {
            dist[*it]=dist[nod]+1;
            q.push(*it);
        }
    }
}

int main()
{
    f>>n>>m>>start;
    dist.resize(n+1,-1);
    G.resize(n+1);
    for(;m;--m)
    {
        f>>x>>y;
        G[x].push_back(y);
    }

    bfs(start);
    for(i=1;i<=n;++i) g<<dist[i]<<' ';
    return 0;
}