1% generated: 16 November 1989 2% option(s): SOURCE_TRANSFORM_1 3% 4% qsort 5% 6% David H. D. Warren 7% Copyright: Public domain 8% 9% quicksort a list of 50 integers 10 11top:-qsort. 12 13qsort :- qsort([27,74,17,33,94,18,46,83,65, 2, 14 32,53,28,85,99,47,28,82, 6,11, 15 55,29,39,81,90,37,10, 0,66,51, 16 7,21,85,27,31,63,75, 4,95,99, 17 11,28,61,74,18,92,40,53,59, 8],_,[]). 18 19qsort([X|L],R,R0) :- 20 partition(L,X,L1,L2), 21 qsort(L2,R1,R0), 22 qsort(L1,R,[X|R1]). 23qsort([],R,R). 24 25partition([X|L],Y,[X|L1],L2) :- 26 X =< Y, !, 27 partition(L,Y,L1,L2). 28partition([X|L],Y,L1,[X|L2]) :- 29 partition(L,Y,L1,L2). 30partition([],_,[],[]). 31