is-odd

main.ts

// example: deno run -A main.ts 52 10

import { decode } from 'https://deno.land/x/[email protected]/mod.ts'
import puppeteer from 'https://deno.land/x/[email protected]/mod.ts'

const isOdd = async (num: number) => {
  const browser = await puppeteer.launch({
    defaultViewport: { width: 1024, height: 1024 },
  })
  try {
    const page = await browser.newPage()
    await page.evaluate(`
      document.body.innerHTML = '<div></div>'.repeat(${num})
      document.head.innerHTML = '<style>' +
        'div { width: 1px; height: 1px; background: red } div:nth-child(odd) { background: blue }' +
        'body { margin: 0; display: grid; grid-template-columns: repeat(1024, 1px); grid-template-rows: repeat(1024, 1px) }'`)

    const [r, g, b, a] = decode(await page.screenshot()).image.slice(4 * (num - 1))
    return r === 0 && g === 0 && b === 255 && a === 255 // blue
  } finally {
    await browser.close()
  }
}

if (import.meta.main) {
  const [x, y] = [parseInt(Deno.args[0]), parseInt(Deno.args[1])]
  console.log(await isOdd(x % (1024 * 1024)) ? x + y : x - y) // odd: add, even: subtract
}