题解 | #字符个数统计#

基本都是字符串处理

import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        if(in.hasNextLine()){
            String line = in.nextLine();
            int count = 0;
            ArrayList<String> list = new ArrayList<String>();
            for(int i=0;i<line.length();i++){
                String s = line.substring(i,i+1);
                if (!list.contains(s))
                {
                    list.add(s);                        
                }
            }
            System.out.println(list.size());
        }
    }
}