Apx

APX

In complexity theory the class APX (an abbreviation of "approximable") is the set of NP optimization problems that allow polynomial-time approximation algorithms with approximation ratio bounded by a constant (or constant-factor approximation algorithms for short). In simple terms, problems in this class have efficient algorithms that can find an answer within some fixed percentage of the optimal answer. For example, there is a polynomial-time algorithm which will find a solution to the bin packing problem that uses at most 5% more than the smallest possible number of bins.