home *** CD-ROM | disk | FTP | other *** search
/ Language/OS - Multiplatform Resource Library / LANGUAGE OS.iso / oper_sys / oasis / ossxmpls.lha / examples / quick.pl < prev    next >
Encoding:
Text File  |  1992-03-25  |  702 b   |  24 lines
  1. /* Prolog version of quicksort benchmark */
  2.  
  3. main :- range(1,I,9999), qsort(_), fail.
  4. main :- qsort(S), write(S), nl.
  5.  
  6. range(L,L,H).
  7. range(L,I,H) :- L<H, L1 is L+1, range(L1,I,H).
  8.  
  9. qsort(S) :- qsort([27,74,17,33,94,18,46,83,65, 2,
  10.                    32,53,28,85,99,47,28,82, 6,11,
  11.                    55,29,39,81,90,37,10, 0,66,51,
  12.                     7,21,85,27,31,63,75, 4,95,99,
  13.                    11,28,61,74,18,92,40,53,59, 8],S,[]).
  14.  
  15. qsort([X|L],R,R0) :-
  16.         partition(L,X,L1,L2),
  17.         qsort(L2,R1,R0),
  18.         qsort(L1,R,[X|R1]).
  19. qsort([],R,R).
  20.  
  21. partition([Y|L],X,[Y|L1],L2) :- Y=<X, partition(L,X,L1,L2).
  22. partition([Y|L],X,L1,[Y|L2]) :- Y>X,  partition(L,X,L1,L2).
  23. partition([],_,[],[]).
  24.