sqort([A|As], Sorted).

biggerThan(Pivot,[],[Pivot]).
biggerThan(Pivot,[A|As], Biggest) :-
  Biggest is [A|biggerThan([A|As|)],
  Pivot <= A.

smallerThan(Pivot,[],[Pivot]).
smallerThan(Pivot,[A|As], Smallest) :-
  Smallest is [A|smallerThan([A|As|)],
  Pivot > A.