If a set of sequences are given, the longest common subsequence problem is to find a common subsequence of all the sequences that is of maximal length.
The longest common subsequence problem is a classic computer science problem, the basis of data comparison programs such as the diff-utility, and has applications in bioinformatics. It is also widely used by revision control systems, such as SVN and Git, for reconciling multiple changes made to a revision-controlled collection of files.