22 lines
644 B
Haskell
22 lines
644 B
Haskell
{-# LANGUAGE BangPatterns #-}
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(%) = mod
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steps = 312
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postNth :: Int -> Int -> [Int] -> Int
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postNth 2018 pos list = list !! (pos + 1)
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postNth n pos list =
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let !newPos = (pos + steps % n + 1) % n
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!newList = take newPos list ++ [n] ++ drop newPos list
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in postNth (n + 1) newPos newList
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oneNth :: Int -> Int -> Int -> Int
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oneNth 50000001 _ oneth = oneth
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oneNth n pos oneth =
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let !newPos = (pos + steps % n + 1) % n
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!newOneth = if newPos == 0 then n else oneth
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in oneNth (n + 1) newPos newOneth
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main :: IO ()
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main = do
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print $ postNth 1 1 [0]
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print $ oneNth 1 1 1 |