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--- Day 1: Sonar Sweep ---
You're minding your own business on a ship at sea when the overboard alarm goes off! You rush to see
if you can help. Apparently, one of the Elves tripped and accidentally sent the sleigh keys flying
into the ocean!
Before you know it, you're inside a submarine the Elves keep ready for situations like this. It's
covered in Christmas lights (because of course it is), and it even has an experimental antenna that
should be able to track the keys if you can boost its signal strength high enough; there's a little
meter that indicates the antenna's signal strength by displaying 0-50 [1m[33mstars[0m.
Your instincts tell you that in order to save Christmas, you'll need to get all [1m[33mfifty
stars[0m by December 25th.
Collect stars by solving puzzles. Two puzzles will be made available on each day in the Advent
calendar; the second puzzle is unlocked when you complete the first. Each puzzle grants
[1m[33mone star[0m. Good luck!
As the submarine drops below the surface of the ocean, it automatically performs a sonar sweep of
the nearby sea floor. On a small screen, the sonar sweep report (your puzzle input) appears: each
line is a measurement of the sea floor depth as the sweep looks further and further away from the
submarine.
For example, suppose you had the following report:
199
200
208
210
200
207
240
269
260
263
This report indicates that, scanning outward from the submarine, the sonar sweep found depths of
199, 200, 208, 210, and so on.
The first order of business is to figure out how quickly the depth increases, just so you know what
you're dealing with - you never know if the keys will get carried into deeper water by an ocean
current or a fish or something.
To do this, count [1m[37mthe number of times a depth measurement increases[0m from the previous
measurement. (There is no measurement before the first measurement.) In the example above, the
changes are as follows:
199 (N/A - no previous measurement)
200 ([1m[37mincreased[0m)
208 ([1m[37mincreased[0m)
210 ([1m[37mincreased[0m)
200 (decreased)
207 ([1m[37mincreased[0m)
240 ([1m[37mincreased[0m)
269 ([1m[37mincreased[0m)
260 (decreased)
263 ([1m[37mincreased[0m)
In this example, there are [1m[37m7[0m measurements that are larger than the previous
measurement.
[1m[37mHow many measurements are larger than the previous measurement?[0m
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