Re^4: move all 0s in an array to the beginning keeping other elements order same

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Re^5: move all 0s in an array to the beginning keeping other elements order same by Laurent_R (Canon) on May 05, 2014 at 06:09 UTC
Thank you, Dave, for your answer, but I think that the merge sort algorithm is inherently stable, independently of its specific implementations. But you are probably right that it is better not to take any cnance and make sure that stability is guaranteed.	[reply]
Re^6: move all 0s in an array to the beginning keeping other elements order same by davido (Cardinal) on May 05, 2014 at 06:35 UTC
What I didn't state clearly in my previous comment is this: In the old days, Perl's sort used a QuickSort algorithm, and it was swapped out, replaced by a Merge Sort starting (if my memory serves) with Perl 5.8. This swap in the implementation of Perl's "sort" was done primarily to avoid the potential for QuickSort to go quadratic on some inputs. A secondary effect was that it provided a stable sort. However unlikely it is that Perl would ever switch again, and this time to an unstable sort, the fact that modern Perls have a stable sort is still just an implementation detail. By specifying "use sort 'stable'", you are making a declaration of what semantics you require, leaving nothing to chance. Additionally, it signals to a future maintainer that this code would not fly if deprived of a stable sort. Dave	[reply]
Re^6: move all 0s in an array to the beginning keeping other elements order same by ikegami (Patriarch) on May 31, 2014 at 04:58 UTC
[ Sorry, missed your reply. ] but I think that the merge sort algorithm is inherently stable But `sort` doesn't necessarily use merge sort. While it's currently the default, it hasn't always been, and it might not always be.	[reply] [d/l]
Re^7: move all 0s in an array to the beginning keeping other elements order same by Laurent_R (Canon) on May 31, 2014 at 08:15 UTC
Thank you ikegami for your answer.	[reply]