
September 9th, 2004, 12:59 PM
#1
What algorithm is faster than Quick Sort?
Gurus,
Are there any algorithms out there that are faster than quick sort?
If so what are they and where can I find more information about them?
Thanks

September 10th, 2004, 05:07 AM
#2
Re: What algorithm is faster than Quick Sort?
Hi engineer2004.
Quicksort is mostly used in programming because it has the best order. Though, there are some algorithms that have a better worst case complexity. Here is a table:
Code:
Order WorstCase
Merge Sort Nlog(N) Nlog(N)
Quick Sort Nlog(N) N^2
Heap Sort Nlog(N) Nlog(N)
Selection Sort N^2 N^2
Of course, the worst case complexity (N^2) is rarely achieved for the quick sort algorithm. Another thing is that Merge sort is easier to implement than the quicksort algorithm, but it uses more memory.
Generally, there are no other faster algorithms than Nlog(N) order. This is for numbers (and strings of course). There are some other algorithms which are ONLY for string sorting which are Norder (they are called Radix  Sort, or sth like that). Generally, search the net for all these algorithms and you'll find much...
Last edited by yiannakop; September 10th, 2004 at 05:12 AM.

September 10th, 2004, 09:18 AM
#3
Re: What algorithm is faster than Quick Sort?
Thanks! Appreciate the answer!

September 27th, 2004, 10:22 AM
#4
Re: What algorithm is faster than Quick Sort?
Hello, I am curious.
Do the three sorting algorithms have same performance? the orders are appeared same, in contrast to your explanation.
Originally Posted by yiannakop
Hi engineer2004.
Quicksort is mostly used in programming because it has the best order. Though, there are some algorithms that have a better worst case complexity. Here is a table:
Code:
Order WorstCase
Merge Sort Nlog(N) Nlog(N)
Quick Sort Nlog(N) N^2
Heap Sort Nlog(N) Nlog(N)
Selection Sort N^2 N^2
Of course, the worst case complexity (N^2) is rarely achieved for the quick sort algorithm. Another thing is that Merge sort is easier to implement than the quicksort algorithm, but it uses more memory.
Generally, there are no other faster algorithms than Nlog(N) order. This is for numbers (and strings of course). There are some other algorithms which are ONLY for string sorting which are Norder (they are called Radix  Sort, or sth like that). Generally, search the net for all these algorithms and you'll find much...

September 27th, 2004, 03:02 PM
#5
Re: What algorithm is faster than Quick Sort?
Radix sort can have better performance for both typical and worst case scenarios. But as with merge sort it requires more memory. It also requires that things be able to be classified in a certain way. Generally, radix sort only works well for integers and strings.
Kevin Hall

September 28th, 2004, 03:48 AM
#6
Re: What algorithm is faster than Quick Sort?
Originally Posted by Shanin
Hello, I am curious.
Do the three sorting algorithms have same performance? the orders are appeared same, in contrast to your explanation.
What I said is that the 3 first algorithms have the same order, but different worstcase complexities. I also mentioned some differences in implementation. I don't see where did I not follow the table...

September 28th, 2004, 09:03 AM
#7
Re: What algorithm is faster than Quick Sort?
Originally Posted by Shanin
Hello, I am curious.
Do the three sorting algorithms have same performance?
Just because two algorithms have the same complexity doesn't mean they are just as efficient or just as fast. It basically tells you how the algorithm performance worsens as the data set grows.
Assume one algorthm always takes exactly 10 times as long as another algorithm to execute. Well both algorithms would hve the same complexity. Complexity is therefore not a good measure of relative performance.
For more information on complexity and "big O notation" look here.
Kevin Hall

September 28th, 2004, 09:07 AM
#8
Re: What algorithm is faster than Quick Sort?
Oh and for the record, radix sort has a typical complexity of O(n).
Kevin Hall
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