내 풀이

class Solution {
    public String solution(String my_string, int num1, int num2) {
        String answer = "";
        String amp = "";
        String[] str = my_string.split("");
        amp = str[num1];
        str[num1] = str[num2];
        str[num2] = amp;
        for(int i = 0 ; i<str.length;i++){
            answer += str[i];    
        }   
        return answer;
    }
}