Cod sursa(job #1315300)

Utilizator lacraruraduRadu Matei Lacraru lacraruradu Data 12 ianuarie 2015 18:41:21
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.07 kb
#include <fstream>
#include <queue>
#include <vector>

using namespace std;

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

const int N = 100001;

vector <int> a[N];
int n,m,s;
queue <int> q;
int cost[N];

void citire()
{
    int i, x, y;
    in >> n >> m >> s;
    for (i = 0; i < m; i++)
    {
        in >> x >> y;
        a[x].push_back(y);
    }
}

/*
parcurg lista de adiacenta a lui x:
for (size_t i = 0; i < a[x].size(); i++)
{
    y = a[x][i];//vecinul (succesorul) curent
    prelucrez y:
}
*/

int main()
{
    citire();

    for(int i = 1; i <= n; i++)
        cost[i] = -1;

    cost[s] = 0;
    q.push(s);

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

        for(size_t i = 0; i < a[x].size(); i++)
        {
            int y = a[x][i];

            if(cost[y] == -1)
            {
                cost[y] = cost[x] + 1;
                q.push(y);
            }
        }
    }

    for(int i = 1; i <= n; i++)
        out << cost[i] << ' ';

    out << '\n';
    return 0;
}