Advent of Code 2023 Day 14: Parabolic Reflector Dish

0:00 Part 1
4:50 Part 2

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[deraileddash]

Wow, this is insanely clever, yet results in such simple, short and clean code!

[mgeo]

Nicely done. I did the same approach, first manually by printing it out to the terminal and then automating it. Your solution is really tidy!

[matteolugli]

for part 1, I did it in another way without the need to flip or change the order of the elements of the original matrix. For each rock I looked at the elements above it, if I encounter a # i set the value of that rock to len(matrix) - i_cord of row_boulder +1. If you end up at the top of the matrix, i set its value to len(matrix). If I encounter another rock I set the value of the rock i am evaluating to encountered rock value - 1. Then I just sum all up. It was quite easy to code, but them I got stuck with this approach for part two. Don't know if there is some sort of way to make it work also for part 2.

[wusswuzz]

I think we can use the Load as a hash or identifier for the grid at any point after a spin cycle. so we can track the load (an int) instead of an entire grid.

[tommygibbons]

Really well done. And thank you for the explanations. Could I ask you to explain how open(0).read() opens the test.txt file please.

[Vancha]

So its an abacus, where some of the beads are stuck to the rail.

[maxxbrandt]

Using tuples of 100 strings as cache keys, array entries and search values feels so wrong but so right, i know, but maybe show the audience that data hashing is used in these cases, to not blow up the RAM? 😅

[AyaanKhan-iyvh]

can anyone tell in which line exactly rotation is happening in part 2...cuz all i see is reversing the rows (in 3rd line of for loop) ??

[gradientO]

this is cool! when i detected a cycle i just incorrectly assumed the cycle length is the iter count, instead of accounting for when cycle begins

[smcr.konsti]

I have some simple functions that examine the fields above, left, below, and right and move the rocks if they're free. For part one, this posed no problem, but for part two, it became quite performance-intensive. I discovered that running through 1000 cycles yielded the same result as running through cycles. The only connection between 1000 and is that 1000^3 equals Can anyone explain if this was just luck or if there's an actual reason?

[mb]

You could just do table instead of set+array like table[string, int], or in Python it's dict really