Vectors instead of hash table in tree building to get x2 speedup
Vectors instead of hash table in tree building to get x2 speedup

ltyscu/FastEfficientP3,ltyscu/Parameter-less_Population_Pyramid,ltyscu/Parameter-less_Population_Pyramid,ltyscu/Parameter-less_Population_Pyramid,brianwgoldman/Parameter-less_Population_Pyramid,brianwgoldman/FastEfficientP3,brianwgoldman/FastEfficientP3,brianwgoldman/Parameter-less_Population_Pyramid,ltyscu/FastEfficientP3,ltyscu/FastEfficientP3,brianwgoldman/Parameter-less_Population_Pyramid,brianwgoldman/Parameter-less_Population_Pyramid,brianwgoldman/FastEfficientP3,ltyscu/Parameter-less_Population_Pyramid