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 sc = new Scanner(System.in);
        String password1 = sc.nextLine();
        String password2 = sc.nextLine();
        System.out.println(Encode(password1));
        System.out.println(Decode(password2));
    }

    /**
     * 加密
     *
     * @param password 需要加密的密码
     * @return 结果
     */
    private static String Encode(String password) {
        StringBuilder res = new StringBuilder();
        for (int i = 0; i < password.length(); i++) {
            char letter = password.charAt(i);
            if (letter >= 'A' && letter <= 'Z') {
                res.append((char) ((letter - 65 + 1) % 26 + 97));
            }
            if (letter >= 'a' && letter <= 'z') {
                res.append((char) ((letter - 97 + 1) % 26 + 65));
            }
            if (letter >= '0' && letter <= '9') {
                res.append((char) ((letter - 48 + 1) % 10 + 48));
            }
        }
        return res.toString();
    }

    /**
     * 解密
     *
     * @param password 需要解密的密码
     * @return 结果
     */
    private static String Decode(String password) {
        StringBuilder res = new StringBuilder();
        for (int i = 0; i < password.length(); i++) {
            char letter = password.charAt(i);
            if (letter >= 'A' && letter <= 'Z') {
                res.append((char) (122 - (90 - letter + 1) % 26));
            }
            if (letter >= 'a' && letter <= 'z') {
                res.append((char) (90 - (122 - letter + 1) % 26));
            }
            if (letter >= '0' && letter <= '9') {
                res.append((char) (57 - (57 - letter + 1) % 10));
            }
        }
        return res.toString();
    }
}