题解 | 卡拉兹函数

const rl = require('readline').createInterface({input: process.stdin})
const iter = rl[Symbol.asyncIterator]()
const readline = async () => (await iter.next()).value

void async function () {
    const num = parseInt(await readline())
    if (num >= 1 && num <= 1e5) {
        if (num % 2 === 0) {
            console.log(num / 2)
        } else {
            console.log(3 * num + 1)
        }
    } else {
        console.log('输入数字非法')
    }
    rl.close()
}()