Create Longestcommonsubsequencesubstringproblem.cpp

[Jyotishmoy12]

// This is a new dynamic programming problem. I have published a research paper // about this problem under the guidance of Professor Rao Li (University of // South Carolina, Aiken) along with my friend. The paper has been accepted by // the Journal of Mathematics and Informatics.The problem is a variation of the // standard longest common subsequence problem. It says that--> "Suppose there // are two strings, X and Y. Now we need to find the longest string, which is a // subsequence of X and a substring of Y."

[Jyotishmoy12]

@AdiChat Please accept the issue with hacktoberfest tag

[Jyotishmoy12]

@AdiChat when will this get merged?