[Lv. 1] 가운데 글자 가져오기

class Solution {
    public String solution(String s) {
        String answer = "";
        String[] str = s.split("");
        int len = str.length;
        if(len % 2 != 0) {answer = str[len/2];}
        else {answer = str[len/2 - 1] + str[len/2];}
        return answer;
    }
}