Revert "optimization: A->B helps B->A with its mapping, but 5 sec slower"

This reverts commit f32e73cd4c4433841c16fa158806259cd863c5a1.
add const to function params
Merge branch 'master' of https://github.com/crizzy/dpdc-exercises

Conflicts:
	exercise3/src/Table.cpp
	exercise3/src/main.cpp
ex1 and ex2 old changes