|Problems? Is your data what you think it is?|
Challenge: Fast Common Substringsby Limbic~Region (Chancellor)
|on Apr 04, 2007 at 01:01 UTC||Need Help??|
Limbic~Region has asked for the
wisdom of the Perl Monks concerning the following question:
Tonight on #perl in freenode, a user asked "What is the fastest way to find the number of substrings two strings have in common?"
The user had working code but wanted to know if it could be made faster without relying on Inline::C. We asked a number of clarifying questions to flesh out the requirements:
It seemed to me that the challenge would be much more interesting if the substring length were allowed to be a range so that's worth bonus points. What is the fastest solution you can come up with in pure perl?
Update: Added definition of substring as well as minor code change assigning hash slice to empty list (f00li5h++).
Update: 2007-04-04 08:25 EST - Thanks to everyone who has contributed so far. I will be posting a Benchmark after work so that folks who want to optimize for a given data set may.
Update: 2007-04-05 08:14 EST - Two days after scheduling to transfer my service to another provider, my ISP mysteriously starts having problems with my account - coincidence? I would appreciate it if someone could post a Benchmark assuming 5,000 pairs of strings ranging in length from 30 to 50 lowercase letters with a desired substring length ranging from 3 to 7.
Cheers - L~R