Most Common Concepts for Coding Interviews 

I have a second channel where I solve the daily leetcode problems: youtube.com/@neetcodeio I curated a list of the 150 most important coding interview problems: neetcode.io/practice

Prepping for Google rn. My initial phone screening was a graph problem that required a hash map adjacency list to determine some minimum time at which all nodes are accessible by every other node. Listen to this man LOL

Since last two days... I am working with your one dimensional dp series. I am solving them using my ways and using recursion. Now going to solve the second last problem based on subsequences. Will be doing the iterative version once i get through this list using the recursion. Believe me, Your series is the best series. 🎉🎉

Excellent advice. Perfect example of think smarter rather then try and memorize everything. Basically you have to do these problems in 30 minutes blind. This is why most interviews are medium level. But even the original optimal solution to medium level problems took way more than 30 minutes to come up with.

So bizarre that while we are looking to be employed by FAANG companies, this man/hero and others like him have parted ways with those same firms and never looked back.

On philosophical standpoint, not being a professional coder, I'd also be inclined to believe your message (if I got it right) that strong grasp of fundamentals is much more useful than the ability to solve a really difficult trivial problem. To my understanding the interviewers (coding or not) want to see that you have a strong and healthy base to learn more and build onto, rather than very specialized memorized skill. Like they want to see your problem solving process, they might not even care if you can solve their test problem or not, but to see your thought process in how you'd start solving it, what's your planning stage like and WHY you are doing what you're doing. That tells them your potential and how easy you are to work with as a member of the team, if they can trust you with unfamiliar stuff.

These are the topics I feel it is most important to study, in order, with the first 10 being *essential*: - Two Pointers - Binary Search - Sliding Window - Trees (DFS, BFS) - Merge Intervals - Backtracking - Stacks - Hash Maps - Heaps - Linked Lists, specifically creating new ones and reversing existing - Greedy - Fast and Slow Pointers - Two Heaps - K-way merge - Top K Elements - Subsets - Matrices - Topological Sort - Dynamic Programming - Tries - Union Find - Bitwise manipulation If you do only 5 problems for the first 10 topics, it's still 50 leetcode problems. Some employers purposefully choose less popular topics, such as Union Find, so its probably better to do problems for all topics if possible

Thanks for using Python! As an aspiring data scientist, you are my savior for data structure and algorithm questions even though I got a degree from a university people considering one of the best in CS. Luckily, the neetcode 150 is more than enough for data science and/or machine learning interviews.

Respect towards you increasing day by day guruji

Basically, these tests give you 30 to 60 minutes per question. You HAVE to be able to do these kinds of problems unconsciously. Reading the problem and comprehending it can take 5 to 10 minutes depending on the layers of obscurity (a story about cherries at dinner parties) and how you're given the inputs (parse some flatfile?) and so you need to immediately identify the solution ("sliding window solution") and then implement the solution in about 25-50 minutes. You will then be graded on whether the solution is the "rightest" (did you just bruteforce the answer? or is it performant?) and whether your code looks neat/clean (or does it look like you LLM'd it). These hazing rituals have gotten so bad that you need to be able to program without thinking to make the time limit, which feels pretty counter to the person you want to hire as an engineer, lol.

Hello sir,thankyou soo much for all your tutorials, I was following your neetcode 150 and I cracked my first job just because of doing your neetcode 150 and some of dev stuff ,you are doing gods work

You reminded me that I'm really only grinding LCs to pass interviews. At some point I seem to have forgotten that... well time to go back to our favorite problem DP 😂😂

Really grateful for your channel and also all of the problems on leet code. I find the best results when I study and practice the problem to learn new ideas and solutions, rather than just complete them for the sake of completing them. Looking forward to checking out your recommended problems

Very appreciative for your content and videos. This information is gold really helps someone like me who is trying to teach themselves everything about programming. Thank you!

Nice video! While the situations presented in leetcode problems are not always realistic, knowing when and how to use certain algorithms and data structures is useful on the job. Just knowing DFS (with back tracking) you can generate mazes without loops, as well as solve any maze. All from the same algorithm!

I signed my Apple swe summer internship offer letter yesterday, and i wanted to thank you. I hope you continue to put out more of such useful videos for free

the thing is now you need to do hundreds of leetcode problems not just for the interview but for online assessments in order to get an interview you gotta get near perfect or perfect scores

You know, not many people reveal their tricks like this. Thanks man!

Thanks a bunch bro, I really needed this rn. There are so many leetcode problems such that I struggle with finding solutions for them. I'll heed your advice, and let's see how it goes... 😊

@Neetcode when are you adding a course for decision trees? I’ve gone through you courses and though it mentions during the dp and backtracking problems a video on just recognizing the pattern would be extremely helpful

you should do data structure, algorithm, programming concept tier list. i think its fun idea

What an amazingly informative video! Incredible job man

Does your pathway reflect the frequency/difficulty questions to learn first in your Pro subscrptions? Or if not would you create a pathway that does focus on this.

Thanks for your content! I'm currently preparing for an online interview with a MANGA company which I'll have in a month from now and maneuver the effort seems to be the smartest thing to do to optimize time, and your videos are helping me in that effort :)

Thank you Neetcode, your content is super helpful!

the only video which can motivate a non coder like me to get through python interview ocean before interviews.... kudos and thanks to bring up this..... channel subscribed...

These tips are eye-opening. Thank you so much.

Very informative Video! Thanks for all the help!

Thank you so much for this video. 🙌

I just want to say thanks. Appreciate you a lot.

Thank you, sir for sharing. Could you please create a video that will show how to learn to deeply understand the basics of algorithm concerts. Please upvote!

just a tip re hashmaps, AVG case is the key word here. Interviewers are usually looking for the worst case performance where HashMaps have O(n) worstcase for every action.

This is helpful, thanks.

Wow this is so informative, thanks a lot!!

Thank you so much for all of your videos and content

Gotta study those DFS and BFS until they become my breakfast meal.

When going through the neetcode 150. Do you recommend doing all the easy/medium problems for one topic then moving on? Or is there a better way

Nice overview, thanks a lot!🙇‍♂

I wish there were practical everyday problems to solve with these algos (maybe there are but no-one talks about them?). If I (personally) don't have cause to use them in my regular coding projects, they just go away. Out of sight out of mind. Advent of Code is excellent for practicing algos by applying them but again, even AoC is just a bunch of puzzles.

I see you have the sliding haircut algorithm implemented already

I would really like to see a neetcode add a daily question based on my progression in the road map. Like you said, some questions are derived from other questions. So a daily question based on which questions I’ve completed to allow me to flex my understanding to conform to a new yet similar problem would be great. Love your videos ❤

Hello, I am adequate at c programming b/c it is the main language taught by my university at the start which is now transitioning to java. After learning about the two I'd like advice on which language to start next python or java script?

🎉very clear

What Concepts should be learned serial-wise to ace the CP ? for ex- array,linklist,dp,tree,etc.

It’s really a forbidden jutsu. 🤣😂😂

Hello, I would like to ask you a question, does the programming language in which I solve LeetCode really matter? The FAANG look differently if I resolve in language X and not Y.

Great channel. As an idea for the next series of videos, please, could you consider FANG frontend related questions Thank you

Im studying CS in college year 2, i know about most of those topics, but if you asked me to code them right know then im not sure i would be able to. Like i can explain to you and give some mathematical demonstrations, but idk if i can implement a heap right away.

""" Hi, What do you think about the time complexity of second function here? At first, it looks like cubic() has O(n^3) but both functions practically scale quadratically, considering the cases below. GPT is confused and gives both answers sometimes. """ def quadratic(n): # O(n^2) count = 0 for a in range(n): for b in range(n): count += 1 print(count) def cubic(n): # O(?) count = 0 for a in range(n): for b in range(n): if a == b: for c in range(n): count += 1 print(count) cubic(20) # 400 (20*20) cubic(30) # 900 (30*30) print() quadratic(20) # 400 (20*20) quadratic(30) # 900 (30*30)

I have no idea what you are talking about in most of the video but I still subscribed because one day I will get there

Neetcode, how do you feel about books? Such as the Algorithm Design Manual or the classic CTCI? It's without a doubt not the fastest method but do you have any experience with these?

Sounds like with some consistent studying I can be interview ready in a month's time with these topics in focus?

Excellent

What drawing app you're using? Thanks

“I’ve done hundreds of problems, why do I still suck?” I felt that one. Way too close to home.

Thanks 🤩

I heard that system design is also important for interviews, are there any good resources that you recommend?

I like this video, so thank you. However, all I feel like I'm getting from this is that you need to learn these things for interviews, not jobs. I'm a frontend engineer who mostly dabbles in Typescript and libraries, yet I'm still required to do LC Medium tests

The amazon backpack in the background is a nice easter egg

Don't know man, currently solving dp problems. Somehow it feels very intuitive (im using top down approach), trying to learn to convert it to bottom up. Occasionally still gets stuck 😅😅

3:37 it would help if there weren't a heap of one letter variables everywhere so I could tell what the code is doing without having to look all around the code for what it is or even what type it is.

literally all the online assessments I've taken have tested on dynamic programming lol

So Neet 🙏

Appreciate some of the advice. Although you probably shouldn’t have showed the Reddit person towards the end.

25 years ago I've heard saying: "Every problem is eventually a graph problem." Just learn graphs. That's it!

Eres bueno, muy bueno

Thanks!

Many companies also expect experienced developers to know the company's stack well. If you are applying for a Full Stack Laravel React developer position you are expected to know PHP Laravel react very well. Most Full Stack positions expect you to know a Front End and Back End Framework. Solving Leetcode problems is not enough to get a job.

Ohh The GodFather I also love your sarcasm 😂😂 favorite topic dynamic programing

Nice Video! There a competition for women on coding- code to win. Can you make a video on how to ace it?

It really is ridiculous that I had to solve leetcode nonsense to get a job where I write crud spring applications

I actually find dynamic programming to be easier than greedy algo. If you understand recursion well from DFS, then you can transform a DP problem into a DFS problem with a memo table. Greedy, on the other hand, has no consistent design patterns and is truly looking a spark on cleverness.

3:02 isnt a tree a DAG. why did you mention it to be undirected?

But how do you study for each one, doing random problems at leetcode? reading random articles about random variations of them? Algorithms and DS is the most chaotic topic in Software Engineering.

It would be better if you make a course or series regarding DSA in python. Because on internet or even in RU-vid there are a few courses of DSA in python available. So for python guys and students and beginners it's really hard to get into. The stereotype of "wtf broz you are learning DSA in python?? Go for java or c++ man" is still around. It would be great if you make it.

Backtracking and graph problems are easier than "simple" array problems for me. I guess i'm just weird.

2:21 - Learning graph

please solve leetcode 654. Maximum Binary Tree using monotonic stack

I had a few questions, I know there a patterns that are asked, you don't need to do 500 questions. But as I didn't do much of graphs and trees, The approach I'm currently taking is to cover the topics and learn it, do the questions. Once it is done then ill move to 150 questions you have to practice them and keep applying in mean meantime!@Neetcode is this approach good or i should just learn 150 questions? i know it is different for everyone but just wanted to know what any of you will do!!

wonder how many programing interview relate videos there are... and how many of these exact video idea most common questions .

4:48, doesn't heapify operation take O(n log n) time?

Tech interview process is broken. Dedicating this much time to solving brain teaser problems like leetcode is a huge waste of time, and its whats wrong with the industry.

I recommend you under each video pin a comment where people will be able in comments to make their suggestions for the topics they want you to cover Kosaraju's Algorithm - this would be my suggestion for you to cover it when you have time

I don't know much about how this stuff is done because I'm not really a developer/programmer by trade (I'm a mathematician), but is this not how stuff is prioritized in normal CS courses? I have my minor in CS, but besides programming 1, 2, and data structures/algorithms, I took all the math-heavy courses and skipped the ones that were about, ironically, actually building or designing systems/apps from scratch. It's kind of ironic that all of these things seem like the entire focus of a math-focused CS course if they aren't touched on as much in the non-math-heavy CS courses.

Quality.

Been doing a lot of interviews lately, admittedly not at MAANG companies, but still F500 companies and honestly haven't had a single coding-style interview in the dozen or so I've had in the last 3 months. Still good to keep these skills sharp incase they come up, but starting to seem less common at the senior level.

“And of course everyone’s favourite: Dynamic programming”

HashMap is really forbidden jutsu

Are you using that filter that makes your eyes look like you are looking at the camera?

Got contacted by the recruiter today. Series B startup. 100-150 people in the company. 30 engineers. Interview for the staff level role. First round - hard level leetcode type of question. Then the 2nd round is another leet code type of coding question. Onsite also has one brain teaser interview question. They are looking for staff level engineers who can design data pipelines and services as well as who can lead junior devs, but 75% of questions are brain teasers. Industry is broken.

❤

The problem i have is optimization I can get the solution but i have to brute force i cant just think of optimized solutions at once

Amazon backpack in the background 🤌

I like how sooo many leetcode hards are graph/dp 😂 they know people are scared of these.

Looking for Google news system design video

bug report: sometimes solved and marked questions don't work on initial load. almost game me a heart attack.

Explain this to Indian employers here. Asking absurd DP questions in OA as well as interview.

I dont wanna be a software engineer at google and i dont want to write code and some code...plz leave me

Cherry Pickup2 gave me nightmares

In Software Engineeriing you don't need to have solved many of those problems, just knowing basic principles are more than enough for absolutely most jobs.