CameronDevDec 5

🎄 - 2025 DAY 5 SOLUTIONS - 🎄

https://programming.dev/post/41848906

🎄 - 2025 DAY 5 SOLUTIONS - 🎄 - programming.dev

# Day 5: Cafeteria ## Megathread guidelines - Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever) - You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://topaz.github.io/paste/ [https://topaz.github.io/paste/] if you prefer sending it through a URL ## FAQ - What is this?: Here is a post with a large amount of details: https://programming.dev/post/6637268 [https://programming.dev/post/6637268] - Where do I participate?: https://adventofcode.com/ [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 [https://programming.dev/post/6631465]

Show threadgedhrel

There’s an alternative approach to merging ranges. Put starting and ending points into a heap then scan it, keeping track of the number of open ranges present. Something like this:

mergeRanges rs = let -- We put in this order so we count openings before closings starts = map (\(a, b) -> (a, -1)) rs ends = map (\(a, b) -> (b, 1)) rs heap = H.fromList (starts ++ ends) :: H.MinHeap (Int, Int) in mergeNo heap where -- not in a range currently mergeNo :: H.MinHeap (Int, Int) -> [R] mergeNo h = case H.view h of Nothing -> [] Just ((a, -1), h') -> mergeYes a 1 h' -- in a range mergeYes :: Int -> Int -> H.MinHeap (Int, Int) -> [R] mergeYes start height h = let Just ((v, delta), h') = H.view h newHeight = height - delta in if newHeight == 0 then (start, v) : mergeNo h' else mergeYes start newHeight h'
Dec 7 at 1:04pmWeb