Re: Merging Linked Lists

From:
Lew <lew@nowhere.com>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 20 Dec 2006 10:58:13 -0500
Message-ID:
<zaudnb9R9MsIwBTYnZ2dnUVZ_o2vnZ2d@comcast.com>
Damo writes:
 >> I (will) have anythng up to 6 Linked Lists of strings. I want to merge
 >> them and remove duplicate entries at the same time.

Daniel Dyer wrote:
 > Is LinkedList the best data structure for your needs? Perhaps a Set
 > would be better if you need no duplicates and don't care about sorting?

Daniel Pitts wrote:
 > Is there any reason not to use a Set instead?

Daniel Pitts wrote:

So. My professional suggestion is to make all of your types "Set" (or
"Collection" is better, depending on what you need to do), and
instantiate with "new HashSet()".


Lee Weiner wrote:
 > The whole reason for a Set to exist is to eliminate duplicates. That's what
 > they do, that's all they do. AFAIC, a Set is the most efficient tool for
 > your requirement.

Daniel Pitts wrote:
 > Actually, a set is likely more efficient in some ways. Also, they are
 > for much more than just eliminating duplicates.
 >
 > For example, they are also for efficient "contains" checks.

Patricia Shanahan wrote:
 > Damo wrote:
 >> My plan was to iterate through the lists , if the first list contains
 >> the current item in the second list,skip it or else insert it into the
 >> corrsponding position in the first list.
 >> this should I think return one List with no duplicates
 >
 > That sounds like an O(n*n) method for merging two lists, each containing
 > n elements, even if you use iterators.
 >
 > Sort-and-merge is O(n log n). You only have to look at the head elements
 > of each list, move the smaller to the result, dropping any duplicates
 > from either list.
 >
 > Dumping all the data into a HashSet is O(n). It is also VERY simple to
 > code, using addAll.

Jhair Tocancipa Triana wrote:

If you don't want duplicates, what about using Sets instead of a
Lists?


Get the hint??

- Lew

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