Advent Of Code

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An unofficial home for the advent of code community on programming.dev!

Advent of Code is an annual Advent calendar of small programming puzzles for a variety of skill sets and skill levels that can be solved in any programming language you like.

AoC 2024

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🦌 - 2024 DAY 2 SOLUTIONS -🦌 (programming.dev)

submitted 1 month ago by [email protected] to c/[email protected]

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Day 2: Red-Nosed Reports

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[–] mykl 5 points 1 month ago* (last edited 1 month ago) (6 children)

Uiua

Uiua is still developing very quickly, and this code uses the experimental tuples function, hence the initial directive.

Try it Live!

# Experimental!
"7 6 4 2 1\n1 2 7 8 9\n9 7 6 2 1\n1 3 2 4 5\n8 6 4 4 1\n1 3 6 7 9"
⊜(⊜⋕⊸≠@\s)⊸≠@\n # Partition at \n, then at space, parse ints.

IsSorted ← +⊃(≍⇌⍆.|≍⍆.)        # Compare with sorted array.
IsSmall  ← /××⊃(>0|<4)⌵↘¯1-↻1. # Copy offset by 1, check diffs.
IsSafe   ← ×⊃IsSmall IsSorted  # Safe if Small steps and Ordered.
IsSafer  ← ±/+≡IsSafe ⧅<-1⧻.   # Choose 4 from 5, check again.

&p/+≡IsSafe .            # Part1 : Is each row safe?
&p/+≡(±+⊃IsSafe IsSafer) # Part2 : Is it safe or safer?

[–] Leavingoldhabits 3 points 1 month ago (1 children)

This looks so alien! Does it work with the full set? The comment says 5, choose 4, but I guess it’s written as n, choose n-1?

[–] mykl 1 points 1 month ago

Yes, it should do. I do run the solutions against the live data, but sometimes tweak the solutions afterwards, so can't always guarantee them :-). I left the comment as 5 choose 4 as it felt clearer in the context of the test data.

It does still feel very alien at times, but I do love being able to think about how to adopt a more arrays-based approach to solving these problems.

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