Cod sursa(job #1024868)

Utilizator dumitrualexAlex Dumitru dumitrualex Data 9 noiembrie 2013 11:29:48
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.08 kb
#include <fstream>
#include <vector>
#include <queue>
#define nmax 100000+5
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
using namespace std;

ifstream fin("bfs.in");
ofstream fout("bfs.out");

int n, m, s;
vector<int> u[nmax];
int pas[nmax];

void citire()
{
    int x, y;
    fin >> n >> m >> s;
    FOR(i, 1, m)
    {
        fin >> x >> y;
        u[x].push_back(y);
    }
}

void bfs(int s)
{
    int nod, v;
    queue<int> coada;
    coada.push(s);
    pas[s] = 1;

    while (!coada.empty())
    {
        nod = coada.front();
        coada.pop();

        if (!u[nod].empty())
            FOR(i, 0, u[nod].size()-1)
            {
                v = u[nod][i];
                if (pas[v] == 0)
                {
                    pas[v] = pas[nod] + 1;
                    coada.push(v);
                }
            }
    }
}

void rezolvare()
{
    bfs(s);
}

void afisare()
{
    FOR(i, 1, n)
        fout << pas[i]-1 << ' ';
    fout << '\n';
}
int main()
{
    citire();
    rezolvare();
    afisare();
    return 0;
}