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Derp

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Advent of Code 2021 - day 1

https://adventofcode.com/2021/day/1

Given a list of numbers, we are asked how many times the next number in the list is larger than the previous. Ie

199 (N/A - no previous measurement)
200 (increased)
208 (increased)
210 (increased)
200 (decreased)
207 (increased)
240 (increased)
269 (increased)
260 (decreased)
263 (increased)
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This can be solved by reducing over the array returning back a pair of (lastNumber, count) in the reduction function. For the starting condition, I want to use Number.NaN to ensure that I do not increase the count for the first iteration.

-- Part 2
This time, instead of measuring the difference between individual measurements, we are now measuring a sliding window of three values. Ie in the first example, we measure whether [199, 200, 208] is larger than [200, 208, 210]. Since the only difference between these two frames are the numbers at the front and the end, I am going to use a comparison function that takes in four numbers and compares the first and last numbers which should tell me if there is an increase or not. I will then move my sliding window of four over the original list.

https://codesandbox.io/s/amazing-satoshi-zbcs7?file=/src/index.ts

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