Correction. Iterative is not the fastest non-lookup algorithm in Perl (at least when you get to big integers). A divide-and-conquer recursive strategy can out-scale it. The reason is that in an iterative strategy you wind up doing many multiplications of a very large number with a small one. Since the large one has O(n*log(n)) digits each time, that winds up being slightly slower than quadratic.

I would be surprised if divide and conquer were the absolute best strategy. But in pure Perl, given the overhead of Perl, I don't think that you'll easily find a faster algorithm.

In reply to Re: Re: What is the fastest pure-Perl implementation of XXX? by tilly
in thread What is the fastest pure-Perl implementation of XXX? by dragonchild

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