For further references, please visit these following links:
- https://www.geeksforgeeks.org/hashing-data-structure/
- https://www.geeksforgeeks.org/implementing-hash-table-open-addressing-linear-probing-cpp/
- https://visualgo.net/en/hashtable
- http://qa.geeksforgeeks.org/4988/qa.geeksforgeeks.org/4988/what-is-perfect-hashing
- https://www.geeksforgeeks.org/cuckoo-hashing/
- https://github.com/Tessil/hopscotch-map