Haskell quick sort sorting?

Question

I run the following Haskell quicksort function (using the merge and sort algorithm):

qsort []=[]
qsort (x:xs) =
  qsort smaller ++ [x] ++ qsort larger
    where
      smaller = [a | a <- xs , a<x ] -- edit
      larger  = [b | b <- xs , b>=x ]

To check the runtime for this for a small large amount of data, I run the code below:

qsort [100000,99999..0]

It takes up to 40 minutes and it still works! Even the list of 100,000 is not so large, therefore:

• How can I process data with a billion data?
• this sorting algorithm (merging and sorting) takes less time in another language such as C #, python ... this is a problem in haskell
• How can I predict the execution time of an algorithm using its complexity?

Answer 1

- n ². , , ( ).

quicksort n log n, , .