Re: project euler 29

[Ben Bacarisse <ben.usenet@bsb.me.uk>]

Francesc Rocher <francesc.rocher@gmail.com> writes:

>> > But Francesc's program doesn't use that method. It only suggests it in 
>> > a comment. The program actually works by building a list, sorting it, 
>> > and counting the groups.
>
>> I only looked briefly and thought it used the factor method to decide if 
>> the power is one that occurs earlier in the sequence. Two trivial 
>> things, starting with Answer as the full NxN count and then decrementing 
>> Answer made me think that was what it was doing. 
>
> Exactly,

I thought so.

> Implementing the equality operator for a**b = x**y is also an
> alternative algorithm.  Using it would require a loop for a in 2..99,
> b in 2..100, x in a+1..100 and y in 2..100.  Is this correct? Or are
> there other constraints?

Well I just stored the unique pairs found so far.  It's not very
efficient, but perfectly fast enough for a,b in [2, 100].

> If anyone is interested, for performance comparison or whatever reason, I can
> provide a stand alone version.

I am curious, but only if it's not too much work.

-- 
Ben.