题解 | #整数与IP地址间的转换#

const readline = require('readline');

const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});
rl.on('line', function (line) {
    if (line.includes('.')){
        toTen(line)
    }else{
        toIP(line)
    }
    
});
function toIP(str:string){
    const bistr = Number(str).toString(2).padStart(32,'0')
    const arr = [bistr.slice(0,8),bistr.slice(8,16),bistr.slice(16,24),bistr.slice(24,32)]
    const res = arr.map(_=>{
        return parseInt(_,2)
    })
    console.log(res.join('.'))
    
}
function toTen(ips:string){
    const ip = ips.split('.')
    const arr = ip.map(_=>{
        return +_
    }).map(_=>{
        return _.toString(2).padStart(8,'0')
    })
    const str  = arr.join('')
    console.log(parseInt(str, 2))
}

数字转n进制字符串 toString(n)

n进制字符串转十进制，parseInt(num, n)