11. Hash Table: Hash Table is a data structure that stores data in an associative manner.

In a hash table, data is stored in an array format, where each data value has its own unique index value.

Access to data becomes very fast if we know the index of the desired data.

12. TreeMap: TreeMap class is like HashMap. TreeMap stores key-value pairs. The main difference is TreeMap sorts the key in ascending order.

TreeMap is sorted as the ordering of its keys, or by a Comparator provided at map creation time, depending on which constructor is used.

13. Segment Tree: A Segment Tree is a data structure that allows answering range queries over an array effectively, while still being flexible enough to allow modifying the array.

14. Binary Indexed Tree: Binary Indexed Tree also called Fenwick Tree provides a way to represent an array of numbers in an array, allowing prefix sums to be calculated efficiently.

15. Suffix Array: A suffix array is a sorted array of all suffixes of a given string. The definition is similar to Suffix Tree which is a compressed trie of all suffixes of the given text.

16. Sparse Table: Sparse Table is a data structure, that allows answering range queries.

It can answer most range queries in O(logn), but its true power is answering range minimum queries. For those queries it can compute the answer in O(1) time.

17. Range Tree: A range tree is defined as an ordered tree data structure to hold a list of points.

It permits all points within a given range to be efficiently retrieved and is typically implemented in two or higher dimensions.

18. Suffix Automation: A suffix automaton is a powerful data structure that allows solving many string-related problems.

19. Suffix Tree: A Suffix tree (also called PAT tree or, in an earlier form, position tree) is a compressed trie containing all the suffixes of the given text as their keys and positions in the text as their values.

20. Heavy-Light Decomposition: Heavy-light decomposition is a fairly general technique that allows us to effectively solve many problems that come down to queries on a tree.