write-ups-challenges-2021-2022/rng_farm/backend/index.js
2021-12-03 00:33:26 +01:00

54 lines
1.5 KiB
JavaScript

const WebSocket = require('ws');
const wss = new WebSocket.Server({
port: 3000
})
function numberToBinary(num) {
const unpadded = (num >>> 0).toString(2)
return unpadded.padStart(Math.ceil(unpadded.length / 8) * 8, '0');
}
function mistery(bin1, bin2) {
return bin1.split('').map((b1, idx) => {
const b2 = bin2.split('')[idx]
if (!(b1 === '0' && b2 === '0') && !(b1 === '1' && b2 === '1'))
return "1"
else
return "0"
}).join('')
}
function randomInt(min, max) {
return Math.floor(Math.random() * (max - min + 1) + min)
}
function bitShift(byte) {
return `${byte[byte.length - 1]}${byte.substring(0, byte.length - 1)}`
}
wss.on('connection', ws => {
let seed = "010010010100011101000011010101000100011001111011011011110100110001100100010011010110001101000100011011110100111001100001010011000110010001111101"
let veggieIndices = "001000000110110111111101000010110110111101100111110000000001110100110000110100001000011000010011110001000001100011110011010110111001000010001111"
ws.on('message', evt => {
const magic = mistery(seed, veggieIndices)
.split('')
.reduce(([first, ...rest], val) =>
first && first.length < 2
? [[...first, val], ...rest]
: [[val], ...(first === undefined ? [] : [first]), ...rest], [])
seed = magic.flatMap(x => x.join('')).join('')
veggieIndices = bitShift(veggieIndices)
ws.send(JSON.stringify(magic.reverse()))
})
})