import java.util.*;

public class Variations<E extends Comparable<E>> implements Iterator<List<E>> {

    public Variations(Set<E> set, int k) {
        if (set == null || k < 0) {
            throw new IllegalArgumentException();
        }
        
        
        
            
    }

    @Override
    public List<E> next() {

    }

    @Override
    public boolean hasNext() {
        
    }
}