An '''eertree''' is a data structure designed for efficient processing of certain palindrome tasks, for instance counting the number of sub-palindromes in an input string. 

The data structure has commonalities to both ''tries'' and ''suffix trees''.
  See links below. 


;Task:
Construct an eertree for the string "eertree", then output all sub-palindromes by traversing the tree.


;See also:
*   Wikipedia entry:   [https://en.wikipedia.org/wiki/Trie trie].
*   Wikipedia entry:   [https://en.wikipedia.org/wiki/Suffix_tree suffix tree] 
*   [https://arxiv.org/abs/1506.04862 Cornell University Library, Computer Science, Data Structures and Algorithms ───► EERTREE: An Efficient Data Structure for Processing Palindromes in Strings].
*EERTREE: An efficient data structure for processing palindromes in strings[https://www.sciencedirect.com/science/article/pii/S0195669817301294]
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