Most Popular Interview Problems Solved: Episode 1 - Two Sum

Hi guys, this is a start of a series on solving some of the most popular interview questions. When I was studying programming problems, I often times had a hard time finding a clear explanation to a solution. It was a bit confusing trying to figure out how someone jumped to the optimal solution without giving any insights to the problem itself. Thus, I decided to share my thought process on some of the popular problems so that you don't have to pay for them :).

NOTE: at 24:10 I said that on average a hash table is O(N) look up, I meant to say it is O(1) look up. NOT O(N).

In this video, I solve the 2 sum problem with the 3 approaches:
Problem Introduction and Analysis (1:32 - 4:04)

1. Check all possible pairs 4:05 - 11:02
2. Sort and Binary Search 11:02 - 16:40
3. Sort and 2 Pointers 16:40 - 21:47
4a. Hash Table and 2 Pass 21:47 - 24:58
4b. Hash Table and 1 Pass 24:58 - 27:57

Comment below for what question I should solve next, if there is a mistake in the video or if you want to share your approach!

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