The Ideal Stocking Stuffer

Advent of Code 2015 Day 4

Part 1

1. How about another game of Chess?
2. Re-writing...
3. Waiting...

How about another game of Chess?

• This puzzle is déjà vu!
• I solved it eight times as part of 2016 Day 5!
• So...solving it once should just be another waiting game!

Re-writing...

My algorithm in pseudocode:

Import my MD5 library
Set index to 0
Do as long as the first five characters in the generated hash are not zeros
  Increment index by 1

My algorithm in JavaScript:

const MD5 = require('crypto-js/md5')
let index = 0, input = 'abcdef'
while (MD5(input + index).toString().slice(0,5) !== '00000') index++
return index

Waiting...

• It took a couple of seconds to run
• Then generated the correct answer!

Part 2

Six zeroes? No problem!

My algorithm in JavaScript:

const MD5 = require('crypto-js/md5')
let index = 0, input = 'abcdef'
while (MD5(input + index).toString().slice(0,6) !== '000000') index++
return index

• It took several seconds to run
• Then generated the correct answer!

I did it!!

• I solved both parts!
• Using a snippet of an algorithm I wrote in a nearly-identical puzzle from the prior year!
• I wrote what may be my shortest Advent of Code program yet, at just four lines when condensed!