Singleton Design Pattern is a creational design pattern. Singleton pattern lets you ensure that only one instance of a class (struct in go)

Netflix System Design: System Design for a video streaming service like Netflix, amazon prime, Youtube.

Consider you are given n non-negative integers say a1, a2, ..., an, where each element in the array represents a point at coordinate (i, ai)

Consider you given an array of integers and a target sum, return indices of two numbers in the array such that they add up to target.