[코딜리티] - Lesson 10.CountFactors

안녕하세요 남갯입니다.

    public int solution(int N) {
        // write your code in Java SE 8
        int result = 1;
        Map<Integer, Integer> hashMap = new HashMap<>();
        int count = 0;
        int beforeDiv = 2;
        int div = 2;
        while (N > 1) {
            if (N % div == 0) {
                N /= div;
                hashMap.put(div, hashMap.getOrDefault(div, 0) + 1);
                //다시 초기화 할필요가 없다
//                div = 2;
            } else {
                div++;
            }
        }
        Iterator iterator = hashMap.keySet().iterator();
        while (iterator.hasNext()){
            result *= (hashMap.get(iterator.next()) + 1);
        }
        return result;
    }

https://app.codility.com/demo/results/training9ACB57-DUD/

    public int solution(int N) {
        // write your code in Java SE 8
        int result = 1;
        Map<Integer, Integer> hashMap = new HashMap<>();
        int count = 0;
        int beforeDiv = 2;
        int div = 2;
        while (N > 1) {
            if (N % div == 0) {
                N /= div;
                hashMap.put(div, hashMap.getOrDefault(div, 0) + 1);
                //다시 초기화 할필요가 없다
                count ++;
//                div = 2;
            } else {
                if(count > 0){
                    result *= (count +1);
                    count = 0;
                }
                div++;
            }
        }
        if(count > 0){
            result *= (count +1);
        }

        return result;
    }

https://app.codility.com/demo/results/training8BTMNQ-PGJ/

이래도 안되네...ㅋㅋㅋ

제곱근의 반이 정수일경우 2배 -1 아닐경우 2배

public int solution(int N) {
    // write your code in Java SE 8
    int result = 0;
    //1..2..3..4..6..8..12..24
    //즉 제곱근까지의 반까지 나눠지는 갯수 x 2 = 총 개수
    double sqrt = Math.sqrt(N);
    for (int i = 1; i <= sqrt; i++) {
        if (N % i == 0) {
            result++;
        }
    }
    int checkint = (int) sqrt;
    result *= 2;
    if (sqrt == checkint) {
        result--;
    }

    return result;
}

https://app.codility.com/demo/results/trainingMEYEQ3-CTH/