题解 | #统计字符#

import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String str = in.nextLine();
        in.close();

        System.out.println(str.length() - str.replaceAll("[A-Za-z]", "").length());
        System.out.println(str.length() - str.replaceAll("\\s", "").length());
        System.out.println(str.length() - str.replaceAll("[0-9]", "").length());
        System.out.println(str.length() - str.replaceAll("[^0-9a-zA-Z\\s]","").length());
    }
}