항해 모의고사

import java.lang.StringBuilder;

public class Main {
    public String solution(int n){
        String answer;
        String charStr = "";
        int sum = 0;
        String intToStr = Integer.toString(n);
        StringBuilder sb = new StringBuilder(intToStr);
        sb.reverse();
        for(int i = 0; i < sb.length(); i++){
            sb.insert(i+1,"+");
            sb.insert(i,sb.charAt(i));
            sb.delete(sb.length()-1,sb.length());
            charStr += sb.charAt(i);
            //sum += Integer.parseInt(strArr.substring(i,i+1));
        }
        while(n>=1){
            sum += n%10;
            n/=10;
        }
        answer = charStr + "=" + sum;
        return answer;
    }

    public static void main(String[] args) {
        Main solution = new Main();
        int newN = 713;
        System.out.println(solution.solution(newN));
    }
}