Hello,
In the thread
http://www.jsoftware.com/pipermail/programming/2009-April/014304.html I
looked into quick sort and selection sort.
Just to bring that definition into context:
selectsort =: ((<./),$:@(]-. <./))^: (1<#)
ss=: (i.<./) ({ , $:@((~:i...@#) # ]))^:(*...@#@]) ]
] data=: 10 ?...@$ 20
6 15 19 12 14 19 0 17 0 14
ss data
0 0 6 12 14 14 15 17 19 19
selectsort data
0 6 12 14 15 17 19
[data=. 10 ? 100
58 7 26 37 41 56 24 80 38 76
( ss data ) -: (selectsort data)
1
The selectsort matches with ss but works on unique data set.
Regards,
Yuva
On Mon, Aug 31, 2009 at 1:02 PM, Roger Hui <[email protected]> wrote:
> A problem not worth solving is not worth solving well?
> For whatever it's worth:
>
> ss=: (i.<./) ({ , $:@((~:i...@#) # ]))^:(*...@#@]) ]
>
> ] data=: 10 ?...@$ 20
> 6 15 19 12 14 19 0 17 0 14
> ss data
> 0 0 6 12 14 14 15 17 19 19
>
>
>
> ----- Original Message -----
> From: Alex Rufon <[email protected]>
> Date: Monday, August 31, 2009 12:49
> Subject: [Jprogramming] Selection Sort
> To: Programming forum <[email protected]>
>
> > I can't sleep so I tried working on Selection Sort which states:
> >
> > First find the smallest element in the array and exchange it
> > with the element in the first position, then find the second
> > smallest element and exchange it with the element in the second
> > position, and continue in this way until the entire array is
> > sorted. Its asymptotic complexity is
> > O<http://rosettacode.org/wiki/O>(n2) making it inefficient on
> > large arrays.
> > http://rosettacode.org/wiki/Selection_sort
> >
> > The best I can do is:
> > selectionSort=: verb define
> > data=. y
> > for_xyz. y do.
> > temp=. xyz_index }. data
> > nvidx=. xyz_index + temp i. <./ temp
> > data=. ((xyz_index, nvidx) { data) (nvidx, xyz_index) } data
> > end.
> > data
> > )
> >
> >
> > NB. We generate 10 random numbers between 0 and 99 and assign to
> > a variable
> >
> > [data=. 10 ? 100
> >
> > 51 18 81 46 11 54 74 63 56 76
> >
> > selectionSort data
> >
> > 11 18 46 51 54 56 63 74 76 81
> >
> > I tried figuring out how to do this without looping but I can't.
> > Can it be done without loops?
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