Cod sursa(job #598856)

Utilizator nervousNervous nervous Data 27 iunie 2011 13:39:42
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.97 kb
#include <fstream>
#include <queue>
#include <cstring>
#include <vector>

#define X1 100001

using namespace std;

ifstream in;
ofstream out;

vector <int> v[X1];
queue <int> q;
int use[X1],level[X1];

inline void bf(int nod)
{
    for(vector <int>::iterator it=v[nod].begin();it!=v[nod].end();++it)
        if(!use[*it])
        {
            use[*it]=1;
            level[*it]=level[nod]+1;
            q.push(*it);
        }

    if(!q.empty())
    {
        nod=q.front();
        q.pop();
        bf(nod);
    }
}

int main()
{
    int M,N,S,x,y;

    in.open("bfs.in");
    in>>N>>M>>S;
    for(;M;--M)
    {
        in>>x>>y;
        v[x].push_back(y);
    }
    in.close();

    memset(use,0,sizeof(use));
    memset(level,-1,sizeof(level));

    use[S]=1;
    level[S]=0;
    q.push(S);
    bf(S);

    out.open("bfs.out");
    for(int i=1;i<=N;++i) out<<level[i]<<' ';
    out<<'\n';
    out.close();

    return 0;
}