题解 | #字符串去重#

import java.util.HashSet;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String str = scanner.nextLine();
        scanner.close();
        HashSet<Character> hs = new HashSet<>();

        //write your code here......
        char[] arr = str.toCharArray();
        for (char c : arr) {
            if (hs.contains(c)) {
                continue;
            } else {
                hs.add(c);
            }
        }

        for (char c:hs) {
            System.out.print(c);
        }
    }
}