Algorithm.hs

-- 2つのリストの差を求める
difList::[Int]->[Int]->Int->[Int]
difList xs ys n = [(xs!!x) - (ys!!x)|x<-[0..n-1]]

readIntList::IO[Int]
readIntList = map read . words <$> getLine
-- IO Stringから整数のリストを読み込む
readArray::IO String -> IO[Int]
readArray = fmap $ map read . words

-- 文字列に含まれる指定した文字の個数を数える
count::[Char] -> Char -> Int
count xs c = length [x| x <- xs, x == c]

-- 2つのリストの差を求める
difList::[Int] -> [Int] -> [Int] -> [Int]
difList (x:xs) (y:ys) sumList
    |xs == [] = sumList++[x-y]
    |otherwise = difList xs ys (sumList++[x-y])
 
--差の絶対値   
absDif x y
    | x > y = x - y
    |otherwise = y - x

--クイックソート
qSort::[Int] -> [Int]
qSort [] = []
qSort (x:xs)
    | xs == [] = [x]
    | otherwise = qSort [y|y<-xs, y < x] ++ [x] ++ qSort [z|z<-xs, z >= x]

--クイックソート(降順)
qSortDesc::[Int] -> [Int]
qSortDesc [] = []
qSortDesc (x:xs)
    | xs == [] = [x]
    | otherwise = qSort [y|y<-xs, y > x] ++ [x] ++ qSort [z|z<-xs, z <= x]

--中央値
median::[Int] -> Int
median xs = 
    let l = length xs
        n = div l 2
        ms = qSort xs
    in if mod l 2 == 0 then
        div ((ms !! (n - 1)) + (ms !! n)) 2
    else
        (ms !! n)
        
--n以下のm乗数のリストを生成
genExp m n = takeWhile (<=n) (iterate (*m) m)
--n以下の累乗数のリストを作成
genExp' n = concat [takeWhile (<= n) (iterate (*x) (x*x))|x<-[2..n]]

--累積和
cumulativeSum:: [Int]->[Int]->[Int]
cumulativeSum [] list = list
cumulativeSum (x:xs) sumList = cumulativeSum xs (sumList++[x + last sumList])