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.hasNext()) { // 注意 while 处理多个 case
            String str = in.nextLine();
            String str2 = in.nextLine();
            System.out.println(enCode(str));
            System.out.println(deCode(str2));
        //}
    }
    /**
     *解密
     */
    public static String deCode(String str){
        StringBuilder sb = new StringBuilder();
        char[] ch = str.toCharArray();
        for(int i = 0;i < ch.length;i++){
            if(ch[i] == '0'){
                sb.append("9");
            }else if(ch[i] == 'a'){
                sb.append("Z");
            }else if(ch[i] == 'A'){
                sb.append("z");
            }else if('a'< ch[i] && ch[i]<= 'z'){
                sb.append(String.valueOf((char)(ch[i] - 32 - 1)));
            }else if('A'< ch[i] && ch[i]<= 'Z'){
                sb.append(String.valueOf((char)(ch[i] - 1 + 32)));
            }else{
                sb.append(String.valueOf((char)(ch[i] - 1)));
            }
        }       
        return sb.toString();
    }

    /**
     *加密
     */
    public static String enCode(String str){
        StringBuilder sb = new StringBuilder();
        char[] ch = str.toCharArray();
        for(int i = 0;i < ch.length;i++){
            if(ch[i] == '9'){
                sb.append("0");
            }else if(ch[i] == 'Z'){
                sb.append("a");
            }else if(ch[i] == 'z'){
                sb.append("A");
            }else if('a'<= ch[i] && ch[i]<= 'y'){
                sb.append(String.valueOf((char)(ch[i] + 1 - 32)));
            }else if('A'<= ch[i] && ch[i]<= 'Y'){
                sb.append(String.valueOf((char)(ch[i] + 1 + 32)));
            }else{
                sb.append(String.valueOf((char)(ch[i] + 1)));
            }
        }       
        return sb.toString();
    }
}