Help with algorithmic complexity in custom merge sort implementation

Posted by bitcycle on Programmers See other posts from Programmers or by bitcycle
Published on 2012-11-24T20:53:34Z Indexed on 2012/11/25 5:17 UTC
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algorithms

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big-o

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algorithm-analysis

I've got an implementation of the merge sort in C++ using a custom doubly linked list. I'm coming up with a big O complexity of n^2, based on the merge_sort() > slice operation. But, from what I've read, this algorithm should be n*log(n), where the log has a base of two.

Can someone help me determine if I'm just determining the complexity incorrectly, or if the implementation can/should be improved to achieve n*log(n) complexity?

If you would like some background on my goals for this project, see my blog. I've added comments in the code outlining what I understand the complexity of each method to be.

Clarification - I'm focusing on the C++ implementation with this question. I've got another implementation written in Python, but that was something that was added in addition to my original goal(s).

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