Is it possible to solve TSORT with Haskell?

I recently decided to learn Haskell by solving Code Chef problems. Unfortunately, the problem TSORT is proving to be quite a challenge (it should not, I think).

As can be seen from the list of submissions, no one solved this problem with Haskell so far: Link

This particular submission can sort a list of 10^6 integers randomly generated in 0.5seconds on my machine, but still failing the 5 seconds time limit on CodeChef.

Any suggestions to solve this problem with Haskell?

Thank you...