allcombinations

gistfile1.txt

import java.util.Arrays;
import java.util.BitSet;
import java.util.*;
import java.util.stream.*;

public class A {
    private static final int NUM_CARDS = 6;
    private static final List<String> cardss = new ArrayList<>(
        List.of("1399","1399","1399","69","69","69"));

    public static void main(String[] args) {
      enumerateAllHands(6);
    }
    
    private static void enumerateAllHands(int n) {
      if (n > NUM_CARDS) {
        throw new IllegalArgumentException();
      }
      int[] cards = new int[n];
      BitSet cardsUsed = new BitSet();
      enumerate(cards, 0, cardsUsed);
    }
    
    private static void enumerate(int[] cards, int from, BitSet cardsUsed) {
      if (from == cards.length) {
        emit(cards);
      } else {
        for (int i = 0; i < NUM_CARDS; i++) {
          if (!cardsUsed.get(i)) {
            cards[from] = i;
            cardsUsed.set(i);
            enumerate(cards, from + 1, cardsUsed);
            cardsUsed.clear(i);
          }
        }
      }
    }
    
    private static void emit(int[] cards) {
        Arrays.stream(cards)
                                    .boxed()
                                    .map(c -> cardss.get(c))
                                    .forEach(System.out::print);
                                    // .collect(Collectors.toList());
        // System.out.println(Arrays.toString(cards));
      //List<?> aa = Arrays.asList(cards);
    //   System.out.println(list.get(0));
      //Arrays.asList(cards).stream().map(c -> cardss.get(c))
      System.out.println();
    }
}