Efficient Optimal Recompression

An efficient variant of an optimal algorithm is presented, which reorganizes data that has been compressed by some on-the-fly compression method, into a more compact form, without changing the decoding procedure. The algorithm accelerates and improves the space requirements of a known technique based on a reduction to a graph-theoretic problem, by reducing the size of the graph, without affecting the efficiency of the solution that is optimal for the given encoding method. The new method can effectively improve any static dictionary compression scheme using a static encoding method, and in particular some LZ77 variants.