import java.util.*;
public class Solution {
    public boolean IsContinuous(int [] numbers) {
        HashSet<Integer> set = new HashSet<Integer>();
        for(int i : numbers){

            if(i != 0 && set.contains(i)){
                return false;
            }
            set.add(i);
        }
        set.remove(0);
        List<Integer> list = new ArrayList<Integer>(set);
        Collections.sort(list);
        if(list.get(list.size() - 1) - list.get(0) <= 4){
            return true;
        }
        return false;

    }
}