[알고리즘문제풀기] 문자 개수 세기

문제

내가 작성한 정답

class Solution {
    public int[] solution(String my_string) {
        int[] answer = new int[52];
        for(char c : my_string.toCharArray()){
            if(Character.isUpperCase(c)){
                answer[c-'A']++; // 대문자 26개 
            } else {
                answer[c-'a'+26]++;
            }
        }
        return answer;
    }
}

다른 사람들의 정답

class Solution {
    public int[] solution(String my_string) {
        int[] answer = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

        for(char ch: my_string.toCharArray()) {
            answer[ch - 'A' - (Character.isLowerCase(ch)?6:0)]++;
        }
        return answer;
    }
}

class Solution {
    public int[] solution(String my_string) {

        int[] answer = new int[52];

        for (char ch : my_string.toCharArray()) {
            int idx = Character.isUpperCase(ch) ? (ch - 'A') : (ch - 'a' + 26);
            answer[idx]++;
        }

        return answer;
    }
}