twoSum | Advent of Code 2020 Day 1

Advent of Code 2020 Day 1 walkthrough in JavaScript!

Table of Contents

00:00 Introduction
00:58 Part 1 - twoSum
12:16 Part 2 - threeSum

[absence]

Not quite sure why it doesn't gain more traction in the machinery of youtube's self-conscious algorithm, but I highly appreciate these additional animations alongside the easily comprehensible explanations. Have just gotten into AOC, so I was looking for someone who provides elaborate answers like yours. Mainly caused by a problem from 2021 that contained an enumeration of random quboids in a given space, where one has to calculate the sum of all volumes while considering two overlapping quboids to cancel out the overlapped section. Yet 3 overlapping quboids lead to the space being acknowledged again etc. :)

[xavierjulien]

Your method of instruction is brilliant, the way you articulate your thought pattern for solving problems is extremely helpful. Bravo!!

[moonyoojin]

It's great to see you back on youtube! We missed you for sure.

[chengshui]

Hi, Alvin, in the threeSum problem, It seems you forgot to think about the duplicate number in the array.

[jimshtepa]

Hello Alvin, thank you for sharing high quality content with us for free. I was wondering if you are going to make similar series covering aoc 2021?

[chengshui]

like in the array [1, 1, 2, 3, 0] and let you find three numbers add up to 3, you may get the wrong answer [1, 1, 1] .

[jipeejoce]

Excellent work !!! Hope you will pursue your efforts and post more content on this channel.

[soiyeon]

You have a wonderful voice and nice technique to teach sth very easy

[sud]

what about the case when the same third number picked also gave the sum, The sum will have dup but array doesnt

[YuyinSports]

Awesome job really enjoyed this video, keep it up!

[NKCSS]

Good and clear explanation :) I did it by sorting the numbers and having various bail-outs (stop looping when sum > target) but this seems a lot more efficient :) I’ve uploaded slight edits of the last 3 days that I live streamed here on YT, feel free to leave some pointers if you have more good tips :)