Cod sursa(job #1639338)

Utilizator justsomedudePalade Thomas-Emanuel justsomedude Data 8 martie 2016 11:51:26
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.12 kb
#include<iostream>
#include<fstream>
#include<vector>
#include<queue>
#define infinit 123456789

using namespace std;

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

vector <int> L[100009];
int N, M, S, d[100009];

void Citire()
{
    int i, j, x, y;
    fin >> N >> M >> S;
    for (i=1; i<=M; i++)
    {
        fin >> x >> y;
        L[x].push_back(y);
    }
    for (i=1; i<=N; i++)
        d[i] = infinit;
}

void BFS(int k)
{
    int i;
    queue <int> q;
    d[k] = 0;
    q.push(k);

    while (!q.empty())
    {
        k = q.front();
        q.pop();

        for (int j=0; j<L[k].size(); j++)
        {
            i = L[k][j];
            if (d[i] == infinit || d[i] > d[k] + 1)
            {
                d[i] = d[k] + 1;
                q.push(i);
            }
        }
    }
}

void Afisare()
{
    int i;
    for (i=1; i<=N; i++)
       if (d[i] != infinit)
        fout << d[i] << " ";
       else
        fout << "-1 ";
    fout << "\n";
}

int main ()
{
    Citire();
    BFS(S);
    Afisare();
    fin.close();
    fout.close();
    return 0;
}