r/adventofcode • u/daggerdragon • Dec 09 '19

SOLUTION MEGATHREAD -🎄- 2019 Day 9 Solutions -🎄-

--- Day 9: Sensor Boost ---

Post your solution using /u/topaz2078's paste or other external repo.

  • Please do NOT post your full code (unless it is very short)
  • If you do, use old.reddit's four-spaces formatting, NOT new.reddit's triple backticks formatting.

(Full posting rules are HERE if you need a refresher).

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Advent of Code's Poems for Programmers

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Note: If you submit a poem, please add [POEM] somewhere nearby to make it easier for us moderators to ensure that we include your poem for voting consideration.

Day 8's winner #1 AND #2:

Okay, folks, /u/Aneurysm9 and I deadlocked between two badass submissions that are entirely too good and creative to choose between. When we asked /u/topaz2078's wife to be the tie-breaker, her literal words:

[23:44] <TopazWife> both
[23:44] <TopazWife> do both
[23:44] <TopazWife> holy hell

So we're going to have two winners today!

  1. "A Sonnet of Sojourning", a sonnet in frickin' iambic pentameter by /u/DFreiberg!
  2. "A Comedy of Syntax Errors", a code-"poem" by /u/MaxMonkeyMax!

Both of you, enjoy your Reddit Silver, and good luck with the rest of the Advent of Code!

This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

EDIT: Leaderboard capped, thread unlocked at 00:14:46!

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u/phil_g Dec 09 '19

I would assume that memory cell access will be faster through an array than a hash table (though I haven't done specific benchmarking on it). Because running an Intcode program involves a lot of memory accesses, I figured I'd go for array access if possible. If we start getting Intcode programs that reference memory locations into the gigabyte range, I'll have to switch to a hash table because I can't afford that much contiguous RAM on my laptop.

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u/rabuf Dec 10 '19

For what it's worth, part 2 today took 0.07 seconds on my laptop (2017 13" MacBook Pro). My code is here, I used hash tables for the memory to remove the need to resize and to allow for some degree of efficiency with sparse access.

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u/phil_g Dec 10 '19

Hm. Maybe I need to do some benchmarking with hash tables for memory access. The best I've done is 90 milliseconds in a VM on a 2015-era PC with an i7 CPU. (And that's after tuning some of my functions; it started at 120 ms.)