fork download
copy 
  1. prime_decomp(N, L) :-
  2.     SN is sqrt(N),
  3. 	prime_decomp_1(N, SN, 2, [], L).
  4.  
  5.  
  6. prime_decomp_1(1, _, _, L, L) :- !.
  7.  
  8. % Special case for 2, increment 1
  9. prime_decomp_1(N, SN, D, L, LF) :-
  10. 	(   0 is N mod D ->
  11. 	    Q is N / D,
  12. 	    SQ is sqrt(Q),
  13. 	    prime_decomp_1(Q, SQ, D, [D |L], LF)
  14. 	;
  15. 	    D1 is D+1,
  16. 	    (	D1 > SN ->
  17. 	        LF = [N |L]
  18. 	    ;
  19. 	        prime_decomp_2(N, SN, D1, L, LF)
  20. 	    )
  21. 	).
  22.  
  23. % General case, increment 2
  24. prime_decomp_2(1, _, _, L, L) :- !.
  25.  
  26. prime_decomp_2(N, SN, D, L, LF) :-
  27. 	(   0 is N mod D ->
  28. 	    Q is N / D,
  29. 	    SQ is sqrt(Q),
  30. 	    prime_decomp_2(Q, SQ, D, [D |L], LF);
  31. 	    D1 is D+2,
  32. 	    (	D1 > SN ->
  33. 	        LF = [N |L]
  34. 	    ;
  35. 	        prime_decomp_2(N, SN, D1, L, LF)
  36. 	    )
  37. 	).
Success #stdin #stdout 0.02s 68352KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
GNU Prolog 1.3.1
By Daniel Diaz
Copyright (C) 1999-2009 Daniel Diaz
https://ideone.com/LfRJZg
language:
Prolog (gprolog 1.4.5)
created:
11 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!