[알고리즘문제풀기] 대문자와 소문자

문제

내가 작성한 정답

class Solution {
    public String solution(String my_string) {
        StringBuilder answer = new StringBuilder();
        for(char c : my_string.toCharArray()) {
            if(Character.isLowerCase(c)) answer.append(Character.toUpperCase(c));
            else answer.append(Character.toLowerCase(c));
        }
        return answer.toString();
    }
}

다른 사람들이 작성한 정답

StreamAPI

import java.util.stream.Collectors;

class Solution {
    public String solution(String myString) {
        return myString.chars()
			        .mapToObj(operand -> String.valueOf((char) (Character.isLowerCase(operand) ? Character.toUpperCase(operand) : Character.toLowerCase(operand))))
			        .collect(Collectors.joining());
    }
}

class Solution {
    public String solution(String my_string) {
        String answer = "";
        for(int i=0; i<my_string.length(); i++){
            char c = my_string.charAt(i);
            if(Character.isUpperCase(c)){
                answer += String.valueOf(c).toLowerCase();
            }else{
                answer += String.valueOf(c).toUpperCase();
            }
        }
        return answer;
    }
}