Class ProductOfNumbers

ProductOfTheLastKNumbers.java:1–22

class ProductOfNumbers {
    ArrayList<Integer> list = new ArrayList<>();
    public ProductOfNumbers() {
        list.clear();
    }
    
    public void add(int num) {
        if(num==0){
            list.clear();
            return;
        }
        int prev = (list.size()==0)?1:list.get(list.size()-1);
        list.add(prev * num);
    }
    
    public int getProduct(int k) {
        int s = list.size();
        if(s<k) return 0;
        else if(s == k) return list.get(s-1);
        else return (list.get(s-1) / list.get(s-1-k));
    }
}

/**
 * Your ProductOfNumbers object will be instantiated and called as such: