42 lines
1.3 KiB
Haskell
Executable File
42 lines
1.3 KiB
Haskell
Executable File
#! /usr/bin/env -S"ANSWER=42" nix-shell
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#! nix-shell -p ghcid
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#! nix-shell -p "haskellPackages.ghcWithPackages (p: with p; [])"
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#! nix-shell -i "ghcid -c 'ghci -Wall' -T main"
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{-# LANGUAGE OverloadedStrings #-}
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-- import Debug.Trace (trace)
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binaryPartitionWalker :: String -> Int -> Int -> (String, Int, Int)
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binaryPartitionWalker ('F':s) begin end =
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binaryPartitionWalker s begin (((end - begin) `div` 2) + begin)
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binaryPartitionWalker ('B':s) begin end =
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binaryPartitionWalker s (((end - begin) `div` 2) + begin + 1) end
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binaryPartitionWalker ('L':s) begin end =
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binaryPartitionWalker ('F':s) begin end
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binaryPartitionWalker ('R':s) begin end =
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binaryPartitionWalker ('B':s) begin end
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binaryPartitionWalker "" b e = ("",b,e)
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binaryPartitionWalker _ _ _ = undefined
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seatID :: String -> Int
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seatID str = row * 8 + seat
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where
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(rowStr, seatStr) = splitAt 7 str
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(_,row,_) = binaryPartitionWalker rowStr 0 127
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(_,seat,_) = binaryPartitionWalker seatStr 0 7
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solvePart1 :: [String] -> Int
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solvePart1 = maximum . (map seatID)
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main :: IO ()
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main = do
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putStrLn "Day 5 - Part 1"
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print $ seatID "FBFBBFFRLR"
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print $ seatID "BFFFBBFRRR"
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print $ seatID "FFFBBBFRRR"
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print $ seatID "BBFFBBFRLL"
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putStrLn $ "Solution of part 1"
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input <- lines <$> readFile "day5/input"
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print $ solvePart1 input
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