[SWEA][JAVA]D3 : Digit sum

https://swexpertacademy.com/main/code/problem/problemDetail.do?problemLevel=3&contestProbId=AWHPiSYKAD0DFAUn&categoryId=AWHPiSYKAD0DFAUn&categoryType=CODE&problemTitle=&orderBy=INQUERY_COUNT&selectCodeLang=ALL&select-1=3&pageSize=10&pageIndex=9 

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자릿수 덧셈 + 형변환을 이용해서 풀었는데

형변환을 많이해서 그런지 생각보다 메모리가 크다 ..

 

 

 

import java.util.*;

public class Solution {
    public static void main(String[] args) {
        Scanner kb = new Scanner(System.in);
        int T = kb.nextInt();
        for (int t = 1; t <= T; t++) {
            long n=kb.nextInt();
            if(n<10) {
                System.out.println("#" + t + " " + n);
                continue;
            }
            int sum=0;
            String s=String.valueOf(n);
            while(s.length()>=2){
                String[] arr=s.split("");
                for(int i=0; i<arr.length; i++) {
                    sum += Integer.parseInt(arr[i]);
                }
                s=String.valueOf(sum);
                sum=0;
            }
            System.out.println("#"+t+" "+s);
        }
    }
}