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June 30, 2004 09:25Subject:

Re: optimizing Short circuiting sort method based on [M]Message ID:

20040630160002.GA25725@abigail.nlOn Thu, Jul 01, 2004 at 12:55:56AM +1000, Paul Fenwick wrote: > G'day Ton/P5P, > > Ton Hospel wrote: > > >Mergesort works well too if you cut off runs at M. > > You're absolutely right. Quicksort throws away unnecessary elements at > the start (except in pathological cases). Mergesort throws them away at > the end (once runs start to become bigger than M). Both of them become > much faster by having M < N. > > In the end, I would expect the complexity to be the same. There is a linear algorithm possible, although that will not sort the M elements. It is possible to find the Mth element of a set of N elements in O (N) time (albeit with a heavy constant). Given the Mth element, finding the first M elements requires another, single, pass over the entire set. In practise however, I'd use a heap with M elements. Pass once over the entire set, and for each element, if it's less than the largest element in the heap, swap it with the largest, and heapify the heap. This will be O (N log M) worst case, and O (N) if the set is already sorted. Abigail

- Re: optimizing Short circuiting sort method based on [M] by John P. Linderman
- RE: optimizing Short circuiting sort method based on [M] by Orton, Yves
- Re: optimizing Short circuiting sort method based on [M] by Glenn Linderman
- Re: optimizing Short circuiting sort method based on [M] by John P. Linderman
- Re: optimizing Short circuiting sort method based on [M] by david nicol
- Re: optimizing Short circuiting sort method based on [M] by Paul Fenwick
- Re: optimizing Short circuiting sort method based on [M] by david nicol
- Re: optimizing Short circuiting sort method based on [M] by John P. Linderman
- Re: optimizing Short circuiting sort method based on [M] by Nicholas Clark
- Re: optimizing Short circuiting sort method based on [M] by Nicholas Clark
- Re: optimizing Short circuiting sort method based on [M] by david nicol
- Re: optimizing Short circuiting sort method based on [M] by Nicholas Clark
- Re: optimizing Short circuiting sort method based on [M] by david nicol
- Re: optimizing Short circuiting sort method based on [M] by Dave Mitchell
- Re: optimizing Short circuiting sort method based on [M] by david nicol
- Re: optimizing Short circuiting sort method based on [M] by Paul Fenwick
- Re: optimizing Short circuiting sort method based on [M] by Nicholas Clark
- Re: optimizing Short circuiting sort method based on [M] by Nicholas Clark
- Re: optimizing Short circuiting sort method based on [M] by david nicol
- more 5.9 sort tests by david nicol
- Re: more 5.9 sort tests by Rafael Garcia-Suarez
- Re: more 5.9 sort tests by david nicol
- Re: more 5.9 sort tests by Nicholas Clark
- Re: more 5.9 sort tests by Rafael Garcia-Suarez
- Re: more 5.9 sort tests by Ronald J Kimball
- Re: more 5.9 sort tests (second draft) by david nicol
- Re: more 5.9 sort tests (second draft) by Rafael Garcia-Suarez
- sort in scalar context, but broken due to inexperience. by David Nicol
- Re: sort in scalar context, but broken due to inexperience. by Dave Mitchell
- Re: sort in scalar context, but broken due to inexperience. by hv
- Re: sort in scalar context, but broken due to inexperience. by david nicol
- Re: sort in scalar context, but broken due to inexperience. by merlyn
- Re: sort in scalar context, but broken due to inexperience. by Rafael Garcia-Suarez
- [PATCH] sort plays nethack in a scalar context (was: sort in scalarcontext, but broken due to inexperience.) by Paul Fenwick
- Re: [PATCH] sort plays nethack in a scalar context (was: sort inscalar context, but broken due to inexperience.) by Rafael Garcia-Suarez
- Re: [PATCH] sort plays nethack in a scalar context by Paul Fenwick
- Re: [PATCH] sort plays nethack in a scalar context by Nicholas Clark
- Re: [PATCH] sort plays nethack in a scalar context by H.Merijn Brand
- Re: [PATCH] sort plays nethack in a scalar context by Nicholas Clark
- Re: [PATCH] sort plays nethack in a scalar context (was: sort in scalar context, but broken due to inexperience.) by merlyn
- Re: sort in scalar context, but broken due to inexperience. by Graham Barr
- Re: sort in scalar context, but broken due to inexperience. by Dave Mitchell
- Re: sort in scalar context, but broken due to inexperience. by Nick Ing-Simmons
- Short circuiting sort by David L. Nicol
- Re: Short circuiting sort by Glenn Linderman
- Re: Short circuiting sort by david nicol
- Re: sort in scalar context, but broken due to inexperience. by david nicol
- Re: sort in scalar context, but broken due to inexperience. by Graham Barr
- Re: Short circuiting sort by John P. Linderman
- Re: Short circuiting sort by Glenn Linderman
- Re: Short circuiting sort by david nicol
- Re: optimizing Short circuiting sort method based on [M] by david nicol
- Re: optimizing Short circuiting sort method based on [M] by Glenn Linderman
- Re: optimizing Short circuiting sort method based on [M] by david nicol
- Re: optimizing Short circuiting sort method based on [M] by Paul Fenwick
- Re: optimizing Short circuiting sort method based on [M] by david nicol
- Re: optimizing Short circuiting sort method based on [M] by Paul Fenwick
- Re: optimizing Short circuiting sort method based on [M] by Glenn Linderman
- Re: optimizing Short circuiting sort method based on [M] by Glenn Linderman
- Re: optimizing Short circuiting sort method based on [M] by perl5-porters
- Re: optimizing Short circuiting sort method based on [M] by Glenn Linderman
- Re: optimizing Short circuiting sort method based on [M] by Nicholas Clark
- Re: optimizing Short circuiting sort method based on [M] by Glenn Linderman
- Re: optimizing Short circuiting sort method based on [M] by david nicol
- Re: optimizing Short circuiting sort method based on [M] by Dave Mitchell
- Re: optimizing Short circuiting sort method based on [M] by david nicol
- Re: optimizing Short circuiting sort method based on [M] by Dave Mitchell
- Re: optimizing Short circuiting sort method based on [M] by Paul Fenwick
**Re: optimizing Short circuiting sort method based on [M]**by Abigail- Re: optimizing Short circuiting sort method based on [M] by david nicol
- Re: optimizing Short circuiting sort method based on [M] by perl5-porters
- Re: optimizing Short circuiting sort method based on [M] by Glenn Linderman
- RE: [PATCH] sort plays nethack in a scalar context by Orton, Yves
- Re: [PATCH] sort plays nethack in a scalar context by Abigail
- Re: [PATCH] sort plays nethack in a scalar context by Rafael Garcia-Suarez
- Re: [PATCH] sort plays nethack in a scalar context by Ovid
- Re: [PATCH] sort plays nethack in a scalar context by Nicholas Clark
- Re: [PATCH] sort plays nethack in a scalar context by david nicol

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