commit 76cf71d6aae85e5cc6692d802ae1ea7ad2ef8879 · drubery.com/aoc2025

+56 -2
src/Day11.hs
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       module Day11 where

     

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       import Debug.Trace

     

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       import qualified Data.Map as Map

     

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       import Data.Map (Map)

     

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       parse :: String -> Map String [String]

     

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       parse = Map.fromList . map parseLine . lines

     

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         where parseLine :: String -> (String, [String])

     

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               parseLine s =

     

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                 let w = words s

     

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                  in (init $ head w, tail w)

     

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       pathCount :: Map String [String] -> String -> String -> Int

     

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       pathCount edges from to =

     

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         let m = Map.fromList [(v, ct v) | v <- Map.keys edges]

     

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             ct v = if v == to then 1 else sum $ map (m Map.!) (edges Map.! v)

     

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          in ct from

     

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       part1 :: String -> String

     

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       part1 _ = "Day 11 part 1"

     

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       part1 input =

     

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         let edges = Map.insert "out" [] $ parse input

     

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          in show $ pathCount edges "you" "out"

     

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       pathCount2 :: Map String [String] -> String -> String -> Int

     

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       pathCount2 edges from to =

     

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         let neitherMemo = Map.fromList [(v, neither v) | v <- Map.keys edges]

     

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             neither v = if v == to then 1 else sum $ map (neitherMemo Map.!) (edges Map.! v)

     

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             withDacMemo = Map.fromList [(v, withDac v) | v <- Map.keys edges]

     

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             withDac v = if v == to then

     

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                           0

     

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                         else if v == "dac" then

     

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                           sum $ map (neitherMemo Map.!) (edges Map.! v)

     

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                         else

     

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                           sum $ map (withDacMemo Map.!) (edges Map.! v)

     

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             withFftMemo = Map.fromList [(v, withFft v) | v <- Map.keys edges]

     

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             withFft v = if v == to then

     

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                           0

     

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                         else if v == "fft" then

     

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                           sum $ map (neitherMemo Map.!) (edges Map.! v)

     

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                         else

     

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                           sum $ map (withFftMemo Map.!) (edges Map.! v)

     

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             withBothMemo = Map.fromList [(v, withBoth v) | v <- Map.keys edges]

     

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             withBoth v = if v == to then

     

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                           0

     

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                          else if v == "dac" then

     

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                            sum $ map (withFftMemo Map.!) (edges Map.! v)

     

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                          else if v == "fft" then

     

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                            sum $ map (withDacMemo Map.!) (edges Map.! v)

     

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                          else

     

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                            sum $ map (withBothMemo Map.!) (edges Map.! v)

     

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          in withBoth from

     

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       part2 :: String -> String

     

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       part2 _ = "Day 11 part 2"

     

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       part2 input =

     

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         let edges = Map.insert "out" [] $ parse input

     

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          in show $ pathCount2 edges "svr" "out"