Branch-and-Bound algorithm

The branch-and-bound algorithm is used to find all the MPRH_Maximum_Parsimony_Principle trees.  It guarantees to find all the MP trees without conducting an exhaustive search.  MEGA also employs the Max-mini branch-and-bound search, which is described in detail in Kumar et al. (1993Kumar_et_al_1993) and Nei and Kumar (2000Nei_and_Kumar_2000, page 123).