This problem was asked by Twitter. You run an e-commerce website and want to record the last N orde ...

A quack is a data structure combining properties of both stacks and queues. It can be viewed as a li ...

On a mysterious island there are creatures known as Quxes which come in three colors: red, green, an ...

This problem was asked by Google. Implement locking in a binary tree. A binary tree node can be loc ...

This problem was asked by Google. In a directed graph, each node is assigned an uppercase letter. W ...