Day 5: Cafeteria
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FAQ
- What is this?: Here is a post with a large amount of details: https://programming.dev/post/6637268
- Where do I participate?: https://adventofcode.com/
- Is there a leaderboard for the community?: We have a programming.dev leaderboard with the info on how to join in this post: https://programming.dev/post/6631465
Uiua
It took me a while to work out the merging of ranges, but I’m very pleased with this solution.
merging ranges
Merging all the ranges first makes both parts faster. Sorting the ranges first means that you only need to compare adjacent pairs of ranges to decide whether they need to remain separate, or can be merged. If the end of the next range is < end of this range you can drop it; if the start of the next range < end of this range replace this with a new range of (start of this range, max of both ends); otherwise just add next to the merged list and repeat…
(EDIT: I realised that Part1 was really slow, so rewrote it, and total time dropped from 140ms to about 4ms, which is nice.)
Run it here
D ← "3-5\n10-14\n16-20\n12-18\n\n1\n5\n8\n11\n17\n32" # D ← &fras"2025day05.txt" # drop your input file on this pane and uncomment this line to test against your own data. Parse ← ∩(⊜⋕⊸∊+@0⇡10)°$"_\n\n_" # split at \n\n; find all digits. Merge ← ⨬(⨬(⊟|⊂⊢⟜(↥∩⊣))◡(≤⊓⊣⊢)|⊙◌)◡(≤∩⊣) # distinct/overlap/contained. Ranges ← ⊙◌⍥⍜⊣(Merge⊙°⊂)◡⋅⧻⊃↙↘1⍆↯∞_2 # Merge pairs of ranges. P₁ ← /+≠∩⌟(˜⨂1˜⊞≥)⍜⍉°⊟ # membership test P₂ ← /+≡(+1/-)⊙◌ # range counts &p⍜now(⊃P₁ P₂ Ranges Parse D)