题解 | #字符串加解密#

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
        // while (in.hasNextInt()) { // 注意 while 处理多个 case
        //     int a = in.nextInt();
        //     int b = in.nextInt();
        //     System.out.println(a + b);
        // }
        System.out.println(encode(in.nextLine()));
        System.out.print(decode(in.nextLine()));
    }

    private static String encode(String s) {
        char[] arr = new char[s.length()];
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (c == 'z') {
                arr[i] = 'A';
                continue;
            }
            if (c == 'Z') {
                arr[i] = 'a';
                continue;
            }
            if (c == '9') {
                arr[i] = '0';
                continue;
            }
            if (c >= 'a' && c < 'z') {
                arr[i] = (char)(c - 31);
                continue;
            }
            if (c >= 'A' && c < 'Z') {
                arr[i] = (char)(c + 33);
                continue;
            }
            if (c >= '0' && c < '9') {
                arr[i] = (char)(c + 1);
                continue;
            }
            arr[i] = c;
        }
        return String.valueOf(arr);
    }

    private static String decode(String s) {
        char[] arr = new char[s.length()];
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (c == 'A') {
                arr[i] = 'z';
                continue;
            }
            if (c == 'a') {
                arr[i] = 'Z';
                continue;
            }
            if (c == '0') {
                arr[i] = '9';
                continue;
            }
            if (c > 'a' && c <= 'z') {
                arr[i] = (char)(c - 33);
                continue;
            }
            if (c > 'A' && c <= 'Z') {
                arr[i] = (char)(c + 31);
                continue;
            }
            if (c > '0' && c <= '9') {
                arr[i] = (char)(c - 1);
                continue;
            }
            arr[i] = c;
        }
        return String.valueOf(arr);
    }
}