Two Sum (4 Qs)

Series of problems related to "Two Sum"

This question is kind of the classic problem in LeetCode. Though it seems like a pretty easy question, through its extension, we could learn a lot.

Related problems (follow the order to solve each problem):

• 0001. Two Sum Hash Table

• 0167. Two Sum II - Input array is sorted Two Pointer

• 0170. Two Sum III - Data structure design Binary Search

• 0653. Two Sum IV - Input is a BST Binary Search Tree + Stack