From 56b390dc29f2f1cf2846dd1c388398b9343f5a1c Mon Sep 17 00:00:00 2001 From: Mia Herkt Date: Wed, 1 Dec 2021 10:11:19 +0100 Subject: [PATCH] Day 1: Add part 2 --- 01/problem.txt | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/01/problem.txt b/01/problem.txt index a63fff5..3ca3a3e 100644 --- a/01/problem.txt +++ b/01/problem.txt @@ -40,3 +40,37 @@ To do this, count the number of times a depth measurement increases from the pre In this example, there are 7 measurements that are larger than the previous measurement. How many measurements are larger than the previous measurement? + +--- Part Two --- + +Considering every single measurement isn't as useful as you expected: there's just too much noise in the data. + +Instead, consider sums of a three-measurement sliding window. Again considering the above example: + +199 A +200 A B +208 A B C +210 B C D +200 E C D +207 E F D +240 E F G +269 F G H +260 G H +263 H +Start by comparing the first and second three-measurement windows. The measurements in the first window are marked A (199, 200, 208); their sum is 199 + 200 + 208 = 607. The second window is marked B (200, 208, 210); its sum is 618. The sum of measurements in the second window is larger than the sum of the first, so this first comparison increased. + +Your goal now is to count the number of times the sum of measurements in this sliding window increases from the previous sum. So, compare A with B, then compare B with C, then C with D, and so on. Stop when there aren't enough measurements left to create a new three-measurement sum. + +In the above example, the sum of each three-measurement window is as follows: + +A: 607 (N/A - no previous sum) +B: 618 (increased) +C: 618 (no change) +D: 617 (decreased) +E: 647 (increased) +F: 716 (increased) +G: 769 (increased) +H: 792 (increased) +In this example, there are 5 sums that are larger than the previous sum. + +Consider sums of a three-measurement sliding window. How many sums are larger than the previous sum?