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我正在学习haskell,我看到的函数定义是:

quickSort (x : xs) = (quickSort less) ++ (x : equal) ++ (quickSort more)
                 where less = filter (< x) xs
                       equal = filter (== x) xs
                       more = filter (> x) xs

是否可以只用一次遍历列表而不是3来编写它？