题解 | 简单密码

import java.util.Scanner;

// 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);
        // 注意 hasNext 和 hasNextLine 的区别

        int[] chars = new int[] {
            2, 2, 2,
            3, 3, 3,
            4, 4, 4,
            5, 5, 5,
            6, 6, 6,
            7, 7, 7, 7,
            8, 8, 8,
            9, 9, 9, 9,
        };


        while (in.hasNextLine()) { // 注意 while 处理多个 case


            String line = in.nextLine();
            for (Character c : line.toCharArray()) {
                if (c >=  'a' && c <= 'z') {
                    System.out.print(chars[c - 'a']);
                } else if (c >= 'A' && c <= 'Z') {
                    if (c == 'Z')
                        System.out.print('a');
                    else
                        System.out.print((char)(c -'A' + 'a' + 1));
                } else {
                    System.out.print(c);
                }
            }

        }
    }
}