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categories: String data structures
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**Eertree**, also known as **palindromic tree**, is a data structure representing all distinct [palindromic](Palindrome) [substrings](Substring) of a [string](String).

## Problems
- [Palindromic Contest](http://acm.timus.ru/problemset.aspx?space=276)
- The Number of Palindromes (HDOJ 3948)
- [Number of Palindromes](http://www.spoj.com/problems/NUMOFPAL/)
- [Palindrome Substring](https://open.kattis.com/problems/palindromesubstring)
- [Palindromes](https://archive.algo.is/ioi/apio/2014/apio2014_problemset.pdf)
- [The Problem to Slow Down You](http://codeforces.com/gym/100548)
- [Lucy and Flowers](https://www.codechef.com/problems/DECORATE) [^1]
- [Build a Palindrome](https://www.hackerrank.com/contests/world-codesprint-5/challenges/challenging-palindromes)
- [Virus synthesis](http://codeforces.com/gym/100543)

## External links
- [EERTREE: An Efficient Data Structure for Processing Palindromes in Strings](http://arxiv.org/pdf/1506.04862v2.pdf)
- [Palindromic tree](http://adilet.org/blog/25-09-14/)
- [Palindromic tree: behind the scenes](http://codeforces.com/blog/entry/13959)
- [A bit more about palindromes](http://codeforces.com/blog/entry/19193)


[^1]: <https://discuss.codechef.com/questions/33450/decorate-editorial>