Cod sursa(job #1929239)

Utilizator CammieCamelia Lazar Cammie Data 17 martie 2017 12:39:35
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.03 kb
#include <fstream>
#include <queue>
#include <vector>

#define MAXN 100002

using namespace std;

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

queue <int> Q;
vector <int> G[MAXN];

int start, z;
int viz[100002], n;

inline void read()
{
    int m, x, y;

    fin >> n >> m >> start;

    for (int i = 1; i <= m; i++)
    {
        fin >> x >> y;
        G[x].push_back(y);
        //G[y].push_back(x);
    }
}

void bf()
{
    Q.push(start);
    viz[start] = 1;

    while (!Q.empty())
    {
        z = Q.front();

        for (vector <int> :: iterator i = G[z].begin(); i != G[z].end(); i++)
        {
            if (viz[*i] == 0)
            {
                viz[*i] = viz[z] + 1;
                Q.push(*i);
            }
        }

        Q.pop();
    }
}

int main ()
{
    read();
    bf();

    for(int i = 1; i <= n; i++)
    {
        //if (viz[i] == 0)
          //  viz[i] = -1;
        fout << viz[i] - 1 << " ";
    }

    fin.close(); fout.close(); return 0;
}