백준 수학 - 1075번 : 나누기

https://www.acmicpc.net/problem/1075

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import java.io.*;
import java.util.*;
public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
		String a = br.readLine();
		int b = Integer.parseInt(br.readLine());
		String ans = "";
		if(a.length()==1) {
			for(int i=1; i<10; i++) {
				if(i%b==0) {
					ans = ans.concat(String.valueOf(i));
					break;
					
				}
			}
			ans = "0".concat(ans);
		}
		else {
			String t2 = a.substring(0,a.length()-2);
			for(int i=0; i<=99; i++) {
				String temp = t2;
				if(i<10) {
					temp = temp.concat("0").concat(String.valueOf(i));
				}
				else {
					temp = temp.concat(String.valueOf(i));
				}
				int num = Integer.parseInt(temp);
				if(num%b==0) {
					String target = String.valueOf(i);
					if(target.length()==1) {
						target = "0".concat(target);
					}
					ans = ans.concat(target);
					break;
				}
			}
		}
		bw.write(ans);
		bw.close();
	}
}

Stringbuilder를 쓰면 메모리 낭비가 더 적을 것 같다.