From: Florian Gross <flgr@...>
Date: 2004-08-28T01:20:37+09:00
Subject: Re: performance comparison

Boris Glawe wrote:

> Hi,

Moin!

Let me point out two small optimizations. Maybe they will accumulate.

>     def find_trip (current_field)
> 
>         @recursion_count += 1
> 
>         current_field.visited = true
>         @num_visited_fields += 1
>        
>         if @num_visited_fields >= @num_fields
>             trip.unshift(current_field)
               @trip.unshift(current_field)
>             return
>         end
> 
>         for neighbour in current_field.neighbours
>            
>             next if neighbour.visited
> 
>             find_trip(neighbour)
>             if @num_visited_fields >= @num_fields
>                 trip.unshift(current_field)
                   @trip.unshift(current_field)
>                 return
>             end
>         end
>     
>         current_field.visited = false
>         @num_visited_fields -= 1
>     end

Another thing you might want to note is that Array#unshift is quite a 
lot slower than Array#push (100000 iterations of #unshift take ~25 
seconds and 100000 iterations of #push only ~0.07 seconds.)

Output however only happens once so you could get away with just 
iterating over the Array in reverse there. (via #reverse_each)

Regards,
Florian Gross