题解 | #字符串加解密#

import java.util.*;
import java.util.regex.Pattern;

public class Main{
    
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String s1 = scanner.nextLine();
        String s2 = scanner.nextLine();
        System.out.println(encryAndDecry(s1,true));
        System.out.println(encryAndDecry(s2,false));

    }


    /**
     * 加密和解密
     * @return
     */
    public static String encryAndDecry(String str,boolean isEn){
        StringBuilder result = new StringBuilder();
        if(str!=null&&str.length()>0){
            for(int i = 0; i<str.length() ;i ++){
                char c = str.charAt(i);
                if(Pattern.matches("[0-9]", c+"")){
                    int it = Integer.parseInt(String.valueOf(c));
                    if(isEn){
                        it++;
                        if(it>9){
                            it=0;
                        }
                    }else{
                        it--;
                        if(it<0){
                            it=9;
                        }
                    }
                    result.append(it);
                }else if(Pattern.matches("[a-z]", c+"")){
                    if(isEn){
                        c++;
                        if(c>'z'){
                            c = 'a';
                        }
                    }else{
                        c--;
                        if(c<'a'){
                            c = 'Z';
                        }
                    }
                    result.append(Character.toUpperCase(c));
                }else if(Pattern.matches("[A-Z]", c+"")){
                    if(isEn){
                        c++;
                        if(c>'Z'){
                            c = 'A';
                        }
                    }else{
                        c--;
                        if(c<'A'){
                            c = 'Z';
                        }
                    }
                    result.append(Character.toLowerCase(c));
                }
            }
        }
        return result.toString();
    }
}