백준(java)학생번호 - 1235

HashSet을 알아본 김에 적용하여 풀어보았다.

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.HashSet;
import java.util.Set;

public class Main {
	public static void main(String[] args) throws Exception{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int N = Integer.parseInt(br.readLine());
		String[]arr = new String[N];
		Set<String> set = new HashSet<String>();
		for(int i=0;i<N;i++) {
			arr[i]= br.readLine();
		}
		int leng = arr[0].length();
		for(int i = 1;i<=leng;i++) {
			for(int j=0;j<N;j++) {
				set.add(arr[j].substring(leng-i));
			}
			if(set.size()==N) {
				System.out.println(i);
				return;
			}
			set.clear();
		}
	}
}