On Wed, 27 Jan 2010 16:44:18 -0800, Carl Banks wrote: >> You're referring to the O(N**2) bit, right? I am sure he knew it was O >> (N*log(N)), which is still worse than O(N) for key. >> >> If he didn't, well, Python has some fundamental flaws in its basic sort >> algorithm. > > Quicksort is O(N**2) worst case, perhaps that's what he meant.
No, apparently I was delusional. > I'm not > sure about timsort but since it's based on quicksort I'd guess it is > O(N**2) or worse, worst case, as well. timsort is actually a mergesort, not a quicksort. You may like to read this: http://svn.python.org/projects/python/trunk/Objects/listsort.txt > Typical case of a sort is still O(N*log(N)) whether using key or cmp. > People recommended against cmp not because of overall algorithmic time > considerations, but because of the number of function calls. cmp > function was called a minimum of N-1 times and typically around N*log2 > (N) times, whereas key was called exactly N times. Since the overhead > of a Python function call was very large compared to the built-in cmp > operation, it usually outweighed the algorithmic time considerations. Yes, that sounds more like it. Thanks for the corrections. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
