Cod sursa(job #719853)

Utilizator vendettaSalajan Razvan vendetta Data 22 martie 2012 09:47:33
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.07 kb
#include <fstream>
#include <vector>
#include <queue>
#define nmax 100005

using namespace std;

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

int n, m, sursa, d[nmax];
vector<int> gf[nmax];
queue<int> q;

void citeste(){

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

}

void rezolva(){

    for(int i=0; i<nmax-1; i++) d[i] = (1<<30);

    d[sursa] = 0;
    q.push(sursa);

    for(; q.size(); ){
        int nod = q.front();
        q.pop();
        for(int i=0; i<gf[nod].size(); i++){
            //am graf orientat ,nu am nevoie de vector de vizitati
            if (d[gf[nod][i]] == (1<<30)){
                d[gf[nod][i]] = d[nod] + 1;
                q.push(gf[nod][i]);
            }
        }
    }

}

void scrie(){

    for(int i=1; i<=n; i++)
        if (d[i] == (1<<30)) g << "-1" << " ";
        else g << d[i] << " ";

}

int main(){

    citeste();
    rezolva();
    scrie();

    f.close();
    g.close();

    return 0;

}