Longest Common Subsequence Problem
Given two sequences, find the length of longest subsequence present in both of them. A subsequence is a sequence that appears in the same relative order, but not necessarily contiguous. For example, "abc","abg","aeg" are subsequences of "abcdefg". So, a string of length N has 2^N different possible subsequences.
References
http://en.wikipedia.org/wiki/Longest_common_subsequence_problem
in action
https://ideone.com/mrPYZW ( gcc )
https://ideone.com/sfThv1 ( gcc )
https://ideone.com/6EcvVr (c++)
https://ideone.com/kf02K5 (c++)
https://ideone.com/SzQ7lP (ruby language)
https://ideone.com/ZlRcR7 (Golang)
https://ideone.com/aoessx (Python 2.7.17 language)