import java.util.*;

class Permutations {
  
  public static void permute(int n, int k) {
    permute(n, k, new HashSet<Integer>(), new int[k]);
  }

  public static void permute(int n, int k, HashSet<Integer> set, int[] permutation) {
    if (set.size() == k)
      doPermute(n, k, set, permutation);
    else {
      for (int i=0; i<n; i++)
        if (!set.contains(i)) {
          permutation[set.size()] = i;
          set.add(i);
          permute(n,k,set,permutation);
          set.remove(i);
        }
    }
  }
  
  public static void doPermute(int n, int k, HashSet<Integer> set, int[] permutation) {
    System.out.println(Arrays.toString(permutation));
    perms++;
  }
  
  private static int perms;
  
  public static void main(String[] args) {
    perms = 0;
    permute(5,3);
    System.out.println(perms);
  }
}