Addition: Palindromic Tree

[ahmed-dardery]

This is my implementation of palindromic tree; a strings data structure that extracts all unique palindromic substrings and their frequencies. Obviously I'm open to suggestions on how to improve it : D

[simonlindholm]

May be worth looking at https://github.com/SuprDewd/CompetitiveProgramming/blob/master/code/strings/eertree.cpp for code golf inspiration