题解 | 字符个数统计

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        Set<Character> set = new HashSet<>();
        String s = scanner.nextLine();
        int result = 0;
        for(int i = 0;i < s.length();i++){
            char c = s.charAt(i);
            if(!set.contains(c) && c >= 0 && c <= 127){
                result++;
                set.add(c);
            }
        }
        System.out.println(result);
    }
}