내 풀이

class Solution {
    public String solution(int age) {
        String answer = "";
        int caseNum = 0;
        String reversAnswer = "";
        while(age>0){
            caseNum = age%10;
            age=age/10;
            switch(caseNum){
            case 1 :
                reversAnswer+='b';    
                break;
            case 2 :
                    reversAnswer+='c';  
                break;        
            case 3 :
                    reversAnswer+='d';  
                break;
            case 4 :
                    reversAnswer+='e';  
                break;
            case 5 :
                    reversAnswer+='f';  
                break;        
            case 6 :
                    reversAnswer+='g';  
                break;
            case 7 :
                    reversAnswer+='h';  
                break;
            case 8 :
                    reversAnswer+='i';  
                break;        
            case 9 :
                    reversAnswer+='j';  
                break;
            case 0 :
                    reversAnswer+='a'; 
                break;                
                }
        }
        for(int i = reversAnswer.length()-1; i >= 0 ; i--){
            answer +=reversAnswer.charAt(i);
        }
        return answer;
    }
}

다른 사람 풀이

class Solution {
    public String solution(int age) {
        String answer = "";
        String[] alpha = new String[]{"a","b","c","d","e","f","g","h","i","j"};
        while(age>0){
            answer = alpha[age % 10] + answer; // 이렇게 하면 자동으로 역순 string 완성됨.
            age /= 10;
        }
        return answer;
    }
}