The program has three classes:one_dimensional_fenvick_tree, pending_one_dimensional_fenvick_tree, two_dimension_fenvick_tree.
- one_dimensional_fenvick_tree - class for a simple one-dimensional fenwick tree
- pending_one_dimensional_fenvick_tree - class with implemented pending operations (The structure no longer has a BIT array. Now we store an array of statuses from which the Fenwick tree is built at the right time)
- two_dimension_fenvick_tree - class with 2D Fenwick tree
All three classes have standard fenwick tree methods such as item update, prefix sum and interval sum.