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Advent of code - Day 10

qmenoret profile image Quentin Ménoret ・1 min read

Are you participating in the Advent of code this year?

If you don't know what the advent of code is, it's a website where you'll find a daily challenge (every day it gets harder). It's a really fun event, you should participate!

I try to solve the exercises using either JavaScript or TypeScript and will share my solutions daily (with one day delay so no one can cheat!). I only share the solution for the second part.

I'm already happy I managed to finish it. I know there are some incredible solutions out there (a colleague of mine solved is with a math equation 🤯), but all I could do was a brute-force. As I often say, IIWIW (If It Works It Works)!

Here is my solution for day #10:

const cache = [];

function valueFor(code, currentValue) {
  if (cache[currentValue]) return cache[currentValue];
  cache[currentValue] = resolve(code, currentValue);
  return cache[currentValue];

function resolve(code, currentValue = 0) {
  if (!code.length) return 1;
  const [first, second, third] = code;
  let result = 0;
  if (first - currentValue > 0 && first - currentValue <= 3)
    result += valueFor(code.slice(1), first);
  if (second - currentValue > 0 && second - currentValue <= 3)
    result += valueFor(code.slice(2), second);
  if (third - currentValue > 0 && third - currentValue <= 3)
    result += valueFor(code.slice(3), third);
  return result;

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Feel free to share your solution in the comments!

Photo by Markus Spiske on Unsplash

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