914. X of a kind in a deck of card

914. X of a kind in a deck of card(my solution).java

    public boolean hasGroupsSizeX(int[] deck) {
        if (deck == null || deck.length <= 1) return false;
        Map<Integer, Integer> map = new HashMap<>();
        for (int i = 0; i < deck.length; i++) {
            int freq = map.getOrDefault(deck[i], 0);
            map.put(deck[i], freq + 1);
        }
        int n = 0; List<Integer> lcf = new ArrayList<>();
        for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
            if (n == 0) {
                lcf = LCF(entry.getValue());
                n++;
            } else {
                for (int i = 0; i < lcf.size(); i++) {
                    if (entry.getValue() % lcf.get(i) != 0) {
                        lcf.remove(i);
                    }
                    if (lcf.isEmpty()) return false;
                }
            }
        }
        return !lcf.isEmpty();
    }
    private List<Integer> LCF(int number) {
        List<Integer> result = new ArrayList<Integer>();
        boolean[] prime = getPrime(number);
        for (int i = 2; i <= number; i++) {
            if (prime[i] && number % i == 0) {
                result.add(i);
                while (number % i == 0) {
                    number = number / i;
                }
                if (number ==  1) {
                    return result;
                }
            }
        }
        return result;
        
    }
    private boolean[] getPrime(int number) {
        boolean[] prime = new boolean[number + 1];
        Arrays.fill(prime, true);
        for (int i = 2; i < prime.length; i++) {
            if (prime[i]) {
                for (int j = 2; i * j <= number; j++) {
                    prime[i * j] = false;
                }
            }
        }
        return prime;
    }