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efficient way of collating (mixing) two linked lists using C

Dear all, 1)In one of our implementation for an application we are supposed to collate two linked lists.The actual problem is like this:

There are two singularly linked lists, the final output will be a "perfectly shuffle" of the lists together into a single list. The new list should consist of consecutively alternating nodes from both lists.Note that both these linked lists have same kind of data structure in their nodes.

solution: The logic which I thought for implementing this is to create temporary node which resembles the nodes in the input linked lists and then copy second node into it,swap the pointers to insert the second lists first node into the first lists second node and proceed so on recursively by inserting the second lists node in between the first lists node.

Is my thinking correct?I believe this is not that efficient way of doing it.Can some one let me know how effectively should we implement this collation between two linked lists?

2)I came across the following code snippet regarding linked lists: struct _tagElement { int m_cRef; unsigned char m_bData[20]; struct _tagElement * m_next;

} NODE, * PNODE;

PNODE DoesWhat (PNODE pn1, PNODE pn2) { PNODE * ppnV = &pn1; PNODE * ppn1 = &pn1; PNODE * ppn2 = &pn2;

for ( ; *ppn1 || *ppn2; ppn1 = &((*ppn1)->m_next)) { if (!(*ppn1) || (0 < memcmp((*ppn1)->m_bData, (*ppn2)->m_bData, sizeof((*ppn2)->m_bData)))) { PNODE pn = *ppn1; *ppn1 = *ppn2; pn2 = (*ppn2)->m_next; (*ppn1)->m_next = pn; } } return *ppnV; } I inferred from this code,that the actual functionality of the function "DoesWhat" is to collate two linked list as stated in query (1) referred in this post.But my friend disagrees.I said that the function doeswhat takes first node of two linked lists(pn1 is first node of linkedlist1,pn2 is first node of linkedlist2-This is my assumption(need not be correct!)),and the code inside inserts nodes of list2 into nodes of list1,also the list will be sorted in increasing order of number of characters present in the array m_bData. Is my understanding and assumption regarding the input params for function "doeswhat" correct?Note that I dont have full code with me,so this code puzzled me,so I have to make it out myself!.

Sorry if it looks too immature to ask,but I thought better learn now then never.I wish I am able to prove to my friend that I am correct,though I am ready to accept my fault incase I am disproved with proper proof.

I appologise incase this OT.Please refer me to proper group incase this is OT.

Looking farward to all your replys and advanced thanks for the same, Regards, s.subbarayan

Reply to
s_subbarayan
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Answer deleted due to later discovery that the OP multi-posted the same query on at least one other newsgroup. This obnoxious behaviour should not be rewarded.

--
"If you want to post a followup via groups.google.com, don't use
 the broken "Reply" link at the bottom of the article.  Click on 
 "show options" at the top of the article, then click on the 
 "Reply" at the bottom of the article headers." - Keith Thompson
Reply to
CBFalconer

The self appointed usenet police.

Yes I top posted to annoy you.

Reply to
Dave

Good b....LONK.

--
"If you want to post a followup via groups.google.com, don't use
 the broken "Reply" link at the bottom of the article.  Click on 
 "show options" at the top of the article, then click on the 
 "Reply" at the bottom of the article headers." - Keith Thompson
Reply to
CBFalconer

Did you have a bad day (or something?) and just do the usenet equivalent of 'going postal' on the OP?

Reply to
Joe

The insistence on posting to one-and-only-one newsgroup is a bit anal. Unless the objection is to the multi-post, rather than appropriately cross-posting. But never attribute to obnoxiousness what can be reasonable explained by ignorance.

The status can be upgraded to obnoxious upon discovery this is not the OP's first offense...

Rufus

Reply to
Rufus V. Smith

Reply to
Richard Henry

This is an unmoderated group, as are the others on which I found your posts. Only you know where you actually posted, so only you can set up a proper cross-posting with follow-ups set.

I am not feeling quite as mean today as I was then. The objective, as ever, is to educate the newbies on usenet so that they don't do these foolish things. I notice you still did not quote any material to which you are replying, and have ignored the advice in my sig. below. This does not bode well for your ability to learn.

--
"If you want to post a followup via groups.google.com, don't use
 the broken "Reply" link at the bottom of the article.  Click on 
 "show options" at the top of the article, then click on the 
 "Reply" at the bottom of the article headers." - Keith Thompson
Reply to
CBFalconer

Mr.CBF, Its good to know you are interested in educating the newby users of usenet.But I believe there are better ways of educating from the approach what you have taken.Looks like bashing to me or any one who reads this.I feel better way is to put anything you want to say in softer note then using harsh words like "foolishness" again in your reply.I believe more then being a professional its good if we are first of all good human beings.While you take interest in educating others,it will be better if you put things in proper way so people get it in right manner.You said I have not learnt to put reply,but it seems you too should be able to learn using polite soft words.By the way the problem why my reply message appeared to you like that(not following quote!) partly because of the problem with google.I still get the old version of usenet in my webpage which did not show any options what you have put in your quote!If only its updated I would be happy enough to follow good things if put in proper way!

Regards, s.subbarayan

Reply to
s.subbarayan

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