On Aug 3, 7:38 am, YannLC <yannlaiglecha...@gmail.com> wrote: > Here is my version,
Thanks Yann! I'm going to write a version in Cython. A guy on the OEIS list got about a 100x speed up with shedskin. Pypy was close to the shedskin mark, and he never finished his Cython port (properly) to judge Cython fairly. > def is_zk(a): > if is_prime(a): return False > d = divisors(a) No need to call is_prime(a), divisors would only return length two; otherwise the sieving is done twice. (Unless Sage does something extra smart behind the scenes.) > s = sum(d) > if s & 1 or s < 2*a: > return False > target = s//2 - a > if target < 2 : return True > m = [0] + [1] * target > d = [i for i in d[1:] if i <= target] > for wi in d: > for w in xrange(target, wi - 1, -1): > m[w] = max(m[w], m[w - wi] + wi) > if m[target] == target: > return True > return False Thanks, I will review this part, I detect you may have more clarity in your dynamic programming style. In my defense, I ported someone else's code. :-) I still like returning the number instead of True. :^) Cheers, Don -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
