인프런 커뮤니티 질문&답변

HashSet으로만 풀었더니 순서를 요구해서 LinkedHashSet으로 풀었습니다.

import java.util.LinkedHashSet;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Main T = new Main();
        Scanner scanner = new Scanner(System.in);
        String input = scanner.next();
        System.out.println(T.solution(input));
    }

    public String solution(String str) {
        String answer = "";
        char[] s = str.toCharArray();

        LinkedHashSet<Character> set = new LinkedHashSet<>();

        for (char c : s) {
            set.add(c);
        }

        for (Character character : set) {
            answer += character;
        }

        return answer;
    }
}