[JAVA] 시저암호

class Solution {
    public String solution(String s, int n) {
        String answer = "";
        
        for(int i=0; i<s.length(); i++){
            char ch = s.charAt(i);
            
            if(Character.isLowerCase(ch)){ //소문자
                ch = (char)((ch-'a'+n)%26 + 'a');
            }
            else if(Character.isUpperCase(ch)){ //대문자
                ch = (char)((ch-'A'+n)%26 + 'A');
            }
            answer += ch;
        }
        return answer;
    }
}