题解 | #字符串加解密#

const readline = require("readline");

const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
});
let num = 0;
rl.on("line", function (line) {
    const tokens = line.split(" ");
    num++;
    // 获取code码， 及将code码转成字符的方法
    if (num === 1) console.log(fn1(line.split("")));
    else if (num === 2) console.log(fn2(line.split("")));
});

// 加密
function fn1(arr) {
    for (let i = 0; i < arr.length; i++) {
        if ("a" <= arr[i] && arr[i] <= "z") {
            arr[i] = String.fromCharCode(
                arr[i].charCodeAt(0) % 122
                    ? (arr[i].charCodeAt(0) % 122) + 1
                    : 97
            ).toLocaleUpperCase();
        } else if ("A" <= arr[i] && arr[i] <= "Z") {
            arr[i] = String.fromCharCode(
                arr[i].charCodeAt(0) % 90 ? (arr[i].charCodeAt(0) % 90) + 1 : 65
            ).toLocaleLowerCase();
        } else if (/[0-9]/.test(arr[i])) {
            arr[i] = (Number(arr[i]) + 1) % 10;
        }
    }

    return arr.join("");
}

// 解密
function fn2(arr) {
    for (let i = 0; i < arr.length; i++) {
        if ("a" <= arr[i] && arr[i] <= "z") {
            arr[i] = String.fromCharCode(
                arr[i].charCodeAt(0) % 123 !== 97
                    ? (arr[i].charCodeAt(0) % 123) - 1
                    : 122
            ).toLocaleUpperCase();
        } else if ("A" <= arr[i] && arr[i] <= "Z") {
            arr[i] = String.fromCharCode(
                arr[i].charCodeAt(0) % 91 !== 65 ? (arr[i].charCodeAt(0) % 91) - 1 : 90
            ).toLocaleLowerCase();
        } else if (/[0-9]/.test(arr[i])) {
            arr[i] = (Number(arr[i]) != 0 ? Number(arr[i]) - 1 : 9) % 10;
        }
    }

    return arr.join("");
}