Contiguous Ordering Problem
Input: A universe U and a set S = {S1, S2, ..., Sm} of subsets of U.
Output: An ordering, b1,b2, ... , bn, of U such that for all i, Si = {bj, bj+1, ..., bj +k} for some j and k. That is each set in S is contiguous in the ordering of U.
In this terminology the U is the set of tags and S is the set of tagged clones.