Sorting: Ep 02 - Selection Sort

[marcellosales]

Great videos... I've been practicing the implementation of algorithms with Java 6/7 and here's my implementation based on your explanation, Wikipedia, etc...

h t t p : // code.google.com/p/programming-­artifacts/source/browse/trunk/­workspaces/hacking/data-struct­ures-impl/src/com/google/code/­datastrut/sort/algorithm/Selec­tionSortStrategy.java

Chears!

[pithikoulis]

This is wrong. There isn't a second array. The array elements are just being swaped.

[lcc0612]

@pithikoulis

Hello, thanks for your comment. Your suggestion works too, and is in fact a more elegant approach to selection sort. However, i chose the method as demonstrated since it's much more intuitive, and becomes easier to understand.

There is no strict rule defining how to implement a sorting algorithm, as long as the concept, in this case the idea of selection, is there.

[mongobot]

@lcc0612

Sorry, but thats just wrong. The main advantage ist that selection sort is an "inplace" sort algorithm, that does not need extra space.

[lcc0612]

@mongobot

I did a bit of reading up, and turns out you're right. The in-place property was actually part of Selection sort's definition, I actually thought it was merely an implementation choice. I'll probably make a video this weekend as an addon to this video.

[Jackpotur]

did you know, I'm a velociraptor and I know the fastest sorting algorithm, but I will not show it until I find someone that matches my speed...

the name of my algorithm is velocirapsort, get it :P

[dreamerr17]

[ lcc0612 ] .. simply, You Are The BEST Of All !

[lcc0612]

@dreamerr17

Thank you very much!

[aboaziz1]

Thanks .. I like it

[lcc0612]

@aboaziz1

Thanks for your kind comment! I'm glad I could be of help!

[dbzkidkev2]

wow... this helped a lot THANKSS

[lcc0612]

@dbzkidkev2

Cheers! Glad I could be of help!

[PUTSAS]

you explain good these sort algorithms, you could make also other videos with radix sort and so on.

[lcc0612]

@PUTSAS

Thanks! I'm not very good with many sorting algorithms (in fact, most of these are self-studied), so I don't really dare to go into those I'm not so sure about!

[frampo4]

Another good tutorial. My only question is I never really got the n-2 or n-1 stuff at the end. Is that essentially saying n-2 (so second from the end?) as a way of classifying the distance to the end for the use in the example?

[lcc0612]

@frampo4

You're thinking in the right direction, though you made a mistake. I'll explain:

By saying "there are n items in the list", we can infer that the last item in the list is also the "nth item" - So if there are 7 items in the list, then the last item would be the 7th item.

So the "n-1"-th item in a list would be the second last item (not n-2, as you incorrectly said). In a list of 7 items, isn't the (n-1 = 7-1)th item, in other words the 6th item, the second last item?

[lcc0612]

You basically get the idea, I hope - The nth item is the last, the (n-1)th is the second last, and so on.

[frampo4]

@lcc0612 Ah ok thanks :)

[aabrification]

Thanks for uploadding..it really helped

[lcc0612]

@aabrification

Cheers! I'm glad I could be a help!

[BeYn11160]

quite useful,,thax :)

[lcc0612]

@BeYn11160

Glad it was a help!