Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
Is there any efficient algorithm that counts the length of Longest Common Palindromic Subsequence of two given strings?
for example:
string 1. afbcdfca
string 2. bcadfcgyfka
the LCPS is 5 and LCPS string is afcfa.
Yes.
Just use an algorithm for LCS for more than two sequences.
If I’m not mistaken, then
It’s up to you to figure out strings #2 and #4.
Update: No, here is a counterexample: LCS( aba, aba, bab, bab ) = ab, ba. The LCS doesn’t ensure the subsequence will be a palindrome, you probably need to add this constraint. Anyway, the recurrence equation for LCS is a good starting point.
If you implement LCS in a generator style, so that it generates all LCS of length n, then n-1, n-2 etc., then you should be able to fairly efficiently compute the longest common member in LCS-gen(string1, reverse-string1), LCS-gen(string2, reverse-string2). But I havn’t checked yet, if there is a highly efficient LCS-gen.