From: "Haris Bogdanoviæ" <fbogdanovi@...>
Date: 2009-07-12T22:25:05+09:00
Subject: Re: one line sorting

It turns out that I was right about having different number of exchanges but 
I was wrong about direction.
If you sort numbers from lowest to biggest you need smaller number of 
exchanges than if you sort in opposite direction.
I made a test and in this particullar list [7,4,9,55,98,11,42] it's 11 
exchanges for smallest to biggest number and 18 for biggest to smallest..


"Haris Bogdanovi�" <fbogdanovi@xnet.hr> wrote in message 
news:h3ciqh$rv8$1@gregory.bnet.hr...
> >The bubblesort you did here will not be faster, no matter what order
>>you traverse the items in. After all, you will look at each item in the
>>outer loop and again at each item in the inner loop again.
>>That makes it n-squared no matter what order you traverse them in.
>
> Just think. If you go from biggest to smallest in inner loop then
> if you put smaller number at the beginning then bigger number
> goes somewhere in the list. If you find even smaller number then exchange
> repeats but the two numbers you exchanged are in better place, the smaller 
> number
> stands before bigger.
> That means that there will be less exchanges needed if you traverse inner 
> loop
> from last to first. Reversing elements will not help.
> So it's true that there will be same number of times going through loops 
> but
> there will be less exchanges needed so that is why it would be faster.
>
>>[1,2,3,4].reverse.each_with_index
>
> As I said that will not help.
> But there is a way to get that speed increment.
> The list has to be sorted from biggest to smallest and then do reverse, 
> but then, reverse takes some time.
>
>