Re: NSArray merge sorting
Re: NSArray merge sorting
- Subject: Re: NSArray merge sorting
- From: Jonathan Hess <email@hidden>
- Date: Mon, 20 Apr 2009 17:39:56 -0700
On Apr 20, 2009, at 5:32 PM, Greg Guerin wrote:
Would NSSet cut the mustard here?
NSArray allows duplicate items; NSSet does not. What do you propose
happen if one or both NSArray inputs have items that compare as equal?
Algorithmically speaking, a merge sort from two inputs into a new
output seems pretty simple. Simply choose the lesser of the two
available next-items and append it to the new array. Or if both
next-items are equal, choose one arbitrarily.
You should probably choose the one that came first in the original
array. Merge sort should be order preserving, and even though the
objects are ordered the same with respect to the comparison function,
their identities my be different and their relative ordering should be
preserved.
Jon Hess
-- GG
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