[Jprogramming] Permutations

[David Mitchell]

I find this helpful to see differences:

    /:~ :/:@": &.>a,b
                      ┌─ ~ ─── /:
                ┌─ : ─┴─ /:
          ┌─ @ ─┴─ ":
   ┌─ &. ─┴─ >
   │
──┤      ┌─ a
   └──────┼─ ,
          └─ b


    /:~:([:/:": )&.>a,b
   ┌─ /:
   │    ┌─ ~:
   │    │          ┌─ [:
──┤    │      ┌───┼─ /:
   │    ├─ &. ─┤   └─ ":
   └────┤      └─ >
        │
        │      ┌─ a
        └──────┼─ ,
               └─ b

--
David Mitchell

On 9/29/2011 5:45, Linda Alvord wrote:
> The only difference between the correct and the incorrect result is a space
> before the second  :  .   Should a space make a difference ever? In the
> correct result I can't understand what it is, what it does and why it does
> it.
>
>     /:~ :/:@":&.>a,b
> ------T-----┐
> │01123│01123│
> L-----+------
>
>
>     /:~:([:/:": )&.>a,b
> 0 1
>
> Since I set out originally to remove "atop", how can I do it?
>
>    /:~ :([: /: ":)&.>a,b
> ------T-----┐
> │10123│32110│
> L-----+------
>
> Hope you can help.  Thanks.  Linda
>
> -----Original Message-----
> From: programming-bounces at jsoftware.com
> [mailto:programming-bounces at jsoftware.com] On Behalf Of Ian Clark
> Sent: Thursday, September 22, 2011 9:13 PM
> To: Programming forum
> Subject: Re: [Jprogramming] Permutations
>
> Off-the-cuff...
>
>     a=: 10123
>     b=: 32110
>     c=: 32100
> -:/ /:~ :/:@":&.>   a,b
> 1
> -:/ /:~ :/:@":&.>   a,c
> 0
>
>
> On Thu, Sep 22, 2011 at 10:41 PM, David Vaughan
> <purpleblues13 at googlemail.com>  wrote:
>> Hi, what is the best (fastest) way to check whether a number is a
> permutation of another number?
>> I've tried listing all permutations of one number and checking whether the
> other number is in the list of permutations. This seems pretty slow, so I
> was hoping for a faster method.
>>
>> Thanks.
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