68 lines
1.3 KiB
Haskell
68 lines
1.3 KiB
Haskell
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import Data.List (sort)
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--------------------
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-- Exercise 1
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--------------------
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flatSort :: [[Integer]] -> [Integer]
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flatSort x = concat (map (\y -> sort y) x)
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-- >>> flatSort [[1,2,3], [1,3,2]]
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-- [1,2,3,1,2,3]
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-- >>> flatSort [[1], [2]]
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-- [1,2]
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-- >>> flatSort [[1], [1,2], [1,2,3]]
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-- [1,1,2,1,2,3]
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--------------------
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-- Exercise 2
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--------------------
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xs :: [[Integer]]
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xs = [[1], [2, 1]]
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-- >>> (concat xs) /= (flatSort xs)
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-- True
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--------------------
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-- Exercise 3
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--------------------
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flatSort' xs =
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case xs of
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[] -> []
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x:xs -> sort x ++ flatSort' xs
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--------------------
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-- Exercise 4
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--------------------
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initial :: String -> String -> Bool
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initial xs ys =
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case xs of
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[] -> True
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x:xs -> (
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case ys of
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[] -> False
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y:ys ->
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if x == y then
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initial xs ys
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else
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False)
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-- >>> initial "abc" "abcd"
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-- True
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-- >>> initial "abc" "xabcd"
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-- False
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--------------------
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-- Exercise 5
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--------------------
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substring :: String -> String -> Bool
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substring xs ys =
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case ys of
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[] -> False
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_ -> initial xs ys || substring xs (tail ys)
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-- >>> substring "abc" "xadbcd"
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-- False
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-- >>> substring "abc" "xadbabccd"
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-- True
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-- >>> substring "abc" "ab"
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-- False
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