题解 | #简单密码#

import java.util.*;
import java.io.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    private static final int UPPERLOWER_OFFSET = 'a' - 'A';
    
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String line = null;
        // 注意 hasNext 和 hasNextLine 的区别
        while ((line = br.readLine()) != null) { // 注意 while 处理多个 case
            char[] password = new char[line.length()];
            for (int i = 0; i < line.length(); ++i) {
                password[i] = transform(line.charAt(i));
            }
            
            System.out.println(password);
        }
    }
    
    public static char transform(char c) {
        if (c >= '0' && c <= '9') {
            return c;
        } else if (c >= 'A' && c <= 'Y') {
            return (char)(c + UPPERLOWER_OFFSET + 1);
        } else if (c == 'Z') {
            return 'a';
        } else if (c >= 'a' && c <= 'c') {
            return '2';
        } else if (c >= 'd' && c <= 'f') {
            return '3';
        } else if (c >= 'g' && c <= 'i') {
            return '4';
        } else if (c >= 'j' && c <= 'l') {
            return '5';
        } else if (c >= 'm' && c <= 'o') {
            return '6';
        } else if (c >= 'p' && c <= 's') {
            return '7';
        } else if (c >= 't' && c <= 'v') {
            return '8';
        } else if (c >= 'w' && c <= 'z') {
            return '9';
        } else {
            throw new RuntimeException("Unexpected Input: " + c);
        }
    }
}