You might know, algorithm almost needs data structure. Any data structure is born with at least one reason. What problems does it solve? Speaking of hash table, it's efficient for complex structure...
Ruby on Rails
In order to design this function we need to know self-join technique first. Now let's have a look. 1. Self-join SELECT employees.*, managers.name as manager FROM users as employees JOIN users as m...
Breadth First Search If you have not known Breadth First Search yet: https://en.wikipedia.org/wiki/Breadth-first_search This is a traditional algorithms we should know cause it would be an efficien...