76 lines
2.7 KiB
Idris
76 lines
2.7 KiB
Idris
import Data.Vect
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import Data.List
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import Data.Fin
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import System.File.ReadWrite
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-- Get windows of a specific size over the data
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windows : {n : Nat} -> List a -> List (Vect n a)
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windows [] = []
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windows {n} xs =
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let (head, _) = splitAt n xs
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tail = drop 1 xs
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in case toVect n head of
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Nothing => []
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(Just x) => x :: windows tail
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findStart : Nat -> List Char -> Maybe Nat
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findStart n cs =
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let segments = windows {n} cs
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in case findIndex (\x => let ( p ** _ ) = nub x in p == n) segments of
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Nothing => Nothing
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(Just x) => Just $ finToNat x + n
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findStartOfPacket : List Char -> Maybe Nat
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findStartOfPacket = findStart 4
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findStartOfMessage : List Char -> Maybe Nat
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findStartOfMessage = findStart 14
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testCases : List (String, Nat, Nat)
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testCases = [("mjqjpqmgbljsphdztnvjfqwrcgsmlb", 7, 19),
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("bvwbjplbgvbhsrlpgdmjqwftvncz", 5, 23),
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("nppdvjthqldpwncqszvftbrmjlhg", 6, 23),
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("nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg", 10, 29),
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("zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw", 11, 26)]
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testCase : (String, Nat, Nat) -> IO Bool
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testCase (string, start, message) =
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do putStrLn $ "Test Case: " ++ string
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putStrLn $ "Expected Start of packet: " ++ show start
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putStrLn $ "Expected Start of message: " ++ show message
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let result = findStartOfPacket (unpack string)
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let messageResult = findStartOfMessage (unpack string)
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putStrLn $ "Evaluated start of packet: " ++ show result
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putStrLn $ "Evaluated start of message: " ++ show messageResult
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let result = not (result == Just start)
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result <- if result
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then do putStrLn "Test Failed!!!"
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pure True
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else if messageResult == Just message
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then do putStrLn "Test Passed"
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pure False
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else do putStrLn "Test Failed!!!"
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pure True
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putStrLn ""
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pure result
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main : IO ()
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main =
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do testsPart1 <- traverse testCase testCases
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if or . map (\x => Delay x) $ testsPart1
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then putStrLn "Failed tests"
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else
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do file <- readFile "input"
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case file of
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Right contents =>
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do putStr "Part 1: "
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putStrLn $ case findStartOfPacket (unpack contents) of
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Just start => show start
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Nothing => "Failed to find start"
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putStr "Part 2: "
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putStrLn $ case findStartOfMessage (unpack contents) of
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Just start => show start
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Nothing => "Failed to find start"
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Left err => printLn err
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