Ex-Google Software Engineer Speeds Through 3 Coding Interview Problems

Рет қаралды 101,869

Жыл бұрын

In this video, I attempt to speed through 3 coding interview questions of progressively increasing difficulty: an easy coding interview problem, a medium coding interview problem, and a hard coding interview question. These are the kinds of coding interview problems that you would get at big tech companies like Google, and they're accessible for free on AlgoExpert.
Easy: www.algoexpert.io/questions/v...
Medium: www.algoexpert.io/questions/r...
Hard: www.algoexpert.io/questions/s...
AlgoExpert: www.algoexpert.io/clem
SystemsExpert: www.systemsexpert.io/clem
MLExpert: www.algoexpert.io/ml
FrontendExpert: www.frontendexpert.io/clem
ProgrammingExpert: www.programmingexpert.io/clem
My LinkedIn: / clementmihailescu
My Twitter: / clemmihai
My Instagram: / clement_mihailescu
Prepping for coding interviews or systems design interviews? Practice with hundreds of video explanations of popular interview questions and a full-fledged coding workspace on AlgoExpert - www.algoexpert.io - and use the promo code "clem" for a discount on the platform!

Пікірлер: 275

@roywastaken Жыл бұрын

Clement has full on transformed into a Super Saiyan

@clem Жыл бұрын

Super Saiyan 2 Gohan in the house! 💪 And this isn't even my final form! 😎

@varun25aggarwal Жыл бұрын

Can't stop laughing🤣

@KevtechITSupport Жыл бұрын

lmao. He went Super Saiyan on python. That snake deserved it.

@juanurdaneta9844 Жыл бұрын

Reminds more of Dash from The Incredibles

@VaibhavSharma-zj4gk Жыл бұрын

@@clem Super saiyan ultra instinct coming soon

@wesleyso0 Жыл бұрын

Wow, Clement's videos just keep getting better! I remember the first video I watched on your channel was the interview with William Lin (that's how I started competitive programming!), so thank you!

@Tyler-jd3ex Жыл бұрын

I love this channel. I could listen to Clement talk about anything

@keyone415 Жыл бұрын

I've seen the rivers size problems once in a big tech interview, it was the exact same problem under a completely different problem statement but the solution was the same :)

@clem Жыл бұрын

😎

@manelessid4210 Жыл бұрын

I like the way you explain your thought process, very easy to follow

@clem Жыл бұрын

Thank you! You'll like AlgoExpert and SystemsExpert then, since I teach most of the video explanations on those products! 👀

@PedroFerreira-kz6mq Жыл бұрын

Great video! Is interesting your linear divide and conquer thought process. Hope one day be good as you.

@remixisthis Жыл бұрын

Clem slowly but surely turning into a Bond villain

@ATTACKM4N Жыл бұрын

"Do you expect me to talk" "No Mr. Bond, I expect you to invert this binary tree!"

@pinklemonade8444 Жыл бұрын

@@ATTACKM4N lmao

@jlecampana Жыл бұрын

Silva?

@IsNgRt 7 ай бұрын

For third problem we can use the Tortoise and Hare algortihm. Have a fast pointer moved k positions front and then start a slow pointer from 0. The time the fast pointer reaches the end, we know that the slow.next is the new head and the slow is the tail!

@jetmirhalili9839 Жыл бұрын

Some small improvements for the second problem: 1. I think you could just change the matrix values from 1 to 0 instead of creating another matrix copy to mark as visited (this would remove O(wh) space complexity) 2. Maybe return a value from traverseThroughRiver (0 or 1 plus the sum of traverse through neighbors) instead of passing an object and change the inner value of it. Edit: Just saw that the O(wh) is the optimal space complexity in AlgoExpert, maybe it needs a recheck 😅

@Charles-kv2xr Жыл бұрын

I think you should assume you can't mutate the input matrix unless otherwise stated or permitted by the interviewer. Just good practice imo. Also, traversing a matrix with either DFS or BFS would still be linear space even if you don't maintain a visited set. I agree with your second point though.

@harisfashion5714 Жыл бұрын

This will modify the input array thought,if permitted we can do

@johannes8144 Жыл бұрын

This doesn't change the space-complexity because of the output array, if the Matrix has the structure of "1,0,1,0;0,1,0,1,0" The amount of lakes is (w*h *1/4) which is still in O(w*h) / the size of the ouput array is O(w*h).

@HHJoshHH Жыл бұрын

Been coding Python for 2 weeks. Everything scares me lol but I physically can't stop. But you make it all fun, Clément. Ty man! Is that the hair that gets the FANNG? I'll never apply to big tech, but I feel like your videos are fun even though I'm never going to interview at Google etc etc. Subbed, notifications = all, like = duh. lol

@eduardolucas9896 Жыл бұрын

Thanks for your videos and for the amazing plataform. What software do you use to explain the solutions handwriting?

@vinit.khandelwal Жыл бұрын

For the hard question, you could simply have moved k positions and then started i from start and j from k deep into linkedlist and moved i and j one step at a time until j was at the end. So you would get i at k places away from end. Then you could have set j.next = root, root = i.next, i.next = null

@charliegray3432 Жыл бұрын

what happens if k is larger than the length of the linkedlist? You would have to wrap around to head if the currentNode.Next == null, this would take the same time complexity as finding length of linked list

@surajhk31 Жыл бұрын

@@charliegray3432 only when k>length of the list not always. So this approach is better than always calculating the length of the list.

@lordeagle2000 8 ай бұрын

@@charliegray3432it can't because of the mod/remainder operation happening earlier ^_^

@Aya-ms6lv Жыл бұрын

great video question: what can be better: mix studying for coding & system design interviews (1 day/1 hr for coding and next 1 day/1 hr for system design) or focus on one part, finish it and switch to the other one? thanks!

@universecode1101 Жыл бұрын

This is very helpful Clement, and 👱🏼‍♂😜Thanks, great job✌🏻

@clem Жыл бұрын

Glad you found it helpful!

@MEvansMusic Жыл бұрын

thinking about the second problem 🤔. could u potentially use a kernel to make this an edge detection problem as opposed to a graph problem? if so would that be more efficient?

@thinhnguyenvan7003 Жыл бұрын

Welcome back, but should you at the end of each solution talk about time and space complexity?

@clem Жыл бұрын

I do! But I forgot to do it for the easy problem, and I went back to it a couple of minutes later, roughly 2 minutes into the medium problem.

@joylinda2673 Жыл бұрын

I love this video; Very informative!

@williamikennanwosu Жыл бұрын

Loving the new look man, it really suits you 👍.

@wadecodez Жыл бұрын

In the river problem's getNeighbors method you had the current row so you should have done matrix[row].length to cover the case that the matrix was jagged.

@Nooop655 Жыл бұрын

Nah, you'll get a run time error for sure.

@connorxiaoyang878 Жыл бұрын

glad to support!

@Gunslinger962 Жыл бұрын

Me: mom I want quicksilver Mom: we have quicksilver at home *Quicksilver at home*

@clem Жыл бұрын

😂

@Nooop655 Жыл бұрын

Why r u asking your mom for quicksilver.

@harispapadopoulos4295 Жыл бұрын

Love these videos!

@clem Жыл бұрын

Glad to hear it!

@fernandoportillo130 Жыл бұрын

i get this and I haven't taken a data structures and algo class lmao so well explained nice!

@manoharvellala666 Жыл бұрын

Hey I subscribed AlgoExpert for one year!And the only one big issue I found out was there is no autocomplete feature in any other languages other than javaScript!!

@sean_haz Жыл бұрын

I did them along with you and got around the same time in each, although I wasn't talking through what I was doing, so I'm probably a little slower than I need to be.

@clem Жыл бұрын

I don't think my speed (or doing all 3 of them in under an hour) is necessarily representative of how fast you need to be. I'd say you're probably very good!

@sachinsanjay2669 Жыл бұрын

Is there a better way to solve the last linked list problem? Because I think it was mentioned to solve inplace

@SK-kj1ge Жыл бұрын

Ooh your hair looks incredible!! Very cool look on you 💈

@deepthisiromani2007 10 ай бұрын

Hi, for the second problem, for the getNeighbours function, why move up (row-1) or to the left(col-1), I'm assuming they'd already be visited. So, just traversing to the right and bottom should be good enough, right? Am I missing something here? Please, do let me know! Thanks in advance.

@hardikvora3744 Жыл бұрын

Nice to see Kakashi attempt a few tests for once!

@-seoulair Жыл бұрын

😂😂😂😂😂😂😂😂😂

@mouathkhatib8668 Жыл бұрын

I've a question about the array methods etc in JS, Is using them in coding interview solutions will be wrong with software engineering questions? Cuz I see in all of your solutions you are focusing on functions, for loops, nested loops and conditional statements. And thank you for your amazing content ❤️

@head0fmob 10 ай бұрын

in my opinion as long as it does not directly solve the question, it should be fine

@__sarik Жыл бұрын

Hi Clement! I bought AlgoExpert and it is going well! Can you tell the name of IDE and the theme that you use on solutions of algoexpert, because I really liked it, but cannt find them. And what is the name of font that u using on current video?

@lordeagle2000 8 ай бұрын

AFAICT they're using the CodeMirror library for the Solutions editor. Unfortunately, it's not a very accessible (a11y) library (at least it wasn't and required a complete rewrite).

@sliu8859 Жыл бұрын

I think modular arithmetic with negative numbers might return a positive number? So -2 mod 5 actually returns 3, therefore maybe the if case for negative is not executed at all. I might be wrong, just my opinion, great video!

@jluis_castro Жыл бұрын

it actually returns -2

@TheDorac1 Жыл бұрын

The bleached hair looks really kick ass but I've had a couple of friends do that and it dries out the hair a lot, making it very brittle, as well as they had quite a bit of hairloss. Maybe it was bad products, I don't know. Just be careful 🙂

@theyruinedyoutubeagain 3 ай бұрын

The third question is quite a bit easier than what you'd see in a real programming interview, though without the expectation to finish it.

@hyper-stack Жыл бұрын

I don't know why but I find that the linked list problem is much easier than the river size :))

@niccoloricardi4827 Жыл бұрын

As others pointed out, an interviewer would probably be looking for a solution to "shifting a linked list" that doesn't require to walk through the whole list to get its length. Again, as other pointed out, you can use two pointers. For k > 0, the second pointer starts at head when the first pointer is at the k-th value. If you increase both pointers at each iteration, when you find the end of the linked list the first pointer tells you where to "cut and sew" the linked list (the second pointer is at the (N-k)-position, with N being the length of the linked list). If k < 0, the point at which you have to cut is the k-th value, and after you found it you walk till the end to have the point to "sew" to.

@lordeagle2000 8 ай бұрын

There are pros/cons to getting the length of the list, esp. since there are many examples of k > len(list). So if k = 1,000 but your list is only 6 items you're moving through the list a thousand times vs. a single time to get the length and reduce to the actual number you need. Optimizations can be done to only calculate on the fly if needed and then to do a remainder operation but that becomes less readable in an interview. Talking about these pros/cons is the difference between a Hire and Strong Hire rating.

@niccoloricardi4827 8 ай бұрын

@@lordeagle2000 the cases where k > len(list_) can be reduced to the procedure I mentioned by applying modulus. I watched the video a long time ago but I think he discussed it at the beginning, didn't he?

@youisstupid2586 Жыл бұрын

Hey man, if you are looking for video ideas, try doing hard coding challenges in code wars or leetcode. It would be fun and educational

@nivedhitaaranganathan701 Жыл бұрын

so the optimal space complexity for problem 2 is constant if we use the given matrix and just probably use another number other than 0/1 to mark the node as visited?

@abdulshabbir573 Жыл бұрын

there will still be space taken up by the recursive call stack as you do the dfs which will be O(n*m) in the worst case

@prom3theus Жыл бұрын

loving the hair, loving the vid even more!

@premthapa9959 Жыл бұрын

Hii i have been attempting to solve the questions in your interviews and for the last question you can use Lists i made a function that takes a head node and den aappends all d next nodes in it in d list such that the list now has all d nodes in order of hierarchy . When k is positive , u just have to List[-1].next = List[0] and List [ len(List)-1-k ].next = None . And ya dis is it for k positive , kinda simple is what i felt and similarly u can do smthing of d sort for k negative . Hope dis comment reaches u

@batman28996 Жыл бұрын

Do more of these, why did you stop?

@yafi2475 Жыл бұрын

How does Javavscript handle modulo of negative number? Modulo of negative number is always positive. Your code should not need to handle negative value of K as you have done the modulo operation before the negative check.

@gokhan1029 4 ай бұрын

Great content.

@joddeveloper7643 Жыл бұрын

Question, for the shifted linked list can't you just use to pointers? first = head.next , second = head.k (meaning if k = 2 then second = head.next.next if 3 second = head.next.next.next) by the time second is pointing to null the we know that first is pointing to our desired new head. I love to know if my thought process is efficient or just garbage. thanks

@alex.does.comedy Жыл бұрын

but you k can be even 100 on a linked list that is maybe just 5 in size, so you kinda always have to loop through the elements.

@joddeveloper7643 Жыл бұрын

@@alex.does.comedy makes sense, thanks

@sickie1961 Жыл бұрын

Better than a purple fringe. Well done

@diamonddew1939 5 ай бұрын

I went through the comments to see if someone explained why k=0 was causing an error in your code- it is because even thought this condition did not execute the while loop, it executes the sewing. i.e it executes as k=1.

@pascal30161 Жыл бұрын

Problem 1: Noob question: Wouldnt it be better to iterate over all the elements of the sequence and have a pointer for the array? That way you can break early if you find all the necessary elements and only have to go through the whole array if the solution turns out to be false or is only found on the last element.

@brberis Жыл бұрын

Not sure but I think the sequence array could be longer that the array.

@hawkmne Жыл бұрын

It doesn't make sense to break early if you're iterating over sequence because the requirement is to find ALL elements of the sequence, so there is no case in which you can break early from sequence iteration. You can only break early from iterating the big array which he does with the "return true" statement.

@kOzae6bI4 Жыл бұрын

I wonder why we can't replace 1 by 0 when visiting matrix[][]. then we don't need a visited matrix at all and can keep space complexity

@patrickudochukwu6280 Жыл бұрын

Hi, I wanted cancelling my mock interview on Algo expert and I didn't where to, also don't know who to sent an email to

@ShabaazShaikz Жыл бұрын

@clement What happened to your hairs And what's your inspiration behind this

@sjoshwa8389 Жыл бұрын

.header{ background : white }

@orisaadele5852 Жыл бұрын

Your videos are great, Instagram is looking forward to hearing from you, thank you!

@joeani8985 Жыл бұрын

Is that a ring see there, Great video.

@dmitriylevy7865 Жыл бұрын

u should do leetcode competition live. this would be more interesting to see how you solve those.

@xuloIsaias Жыл бұрын

wow you look so stable in your ssj1 transformation

@sidforreal Жыл бұрын

My man got a role in Marvel, Congrats!!

@matrixRule127 Жыл бұрын

Header file has changed, need to build the code again 😅

@assafco1000 Жыл бұрын

Have I missed something in question one? You solved it as if the numbers are unique and appear only once but I didn't see that it was mentioned in the question.

@Sportsandgames6 Жыл бұрын

His solution works for uniqueness too, is there a part of the code that makes you think it doesn't?

@assafco1000 Жыл бұрын

@@Sportsandgames6 but what if number are not unique and can repeat multiple times?

@Sportsandgames6 Жыл бұрын

@@assafco1000 his solution still works, it doesn't matter if numbers are duplicated, because he just has a pointer to each number in the sequence and makes sure it's found in the array before moving on. So if the sequence has 2 4's, the array needs 2 4's as well. Do you have a counter example of an input with duplicates that you think won't work?

@aminehl6025 Жыл бұрын

I really like the new hair cut. And the video content

@ilikepizza123100 Жыл бұрын

Could anyone explain why in the last problem head accounts for the linked list, but is also used to mark the first node in the linked list? Or am I wrong? If so, how is the function incorporating the length of the linked list while only being given (head, k)?

@ilikepizza123100 Жыл бұрын

perhaps better question is, if the function returns newHead, how does that answer the question of "what is the new list created"? Is the newHead not a single node?

@edergillian Жыл бұрын

Usually a linked list is represented by its head, as it has the pointer for the next node in the list, which points to the next one, and so on and so forth. So, the only info needed is the head. In the “Cracking the code interview” book, she makes a case where you might want to wrap the whole linked list data structure with another object for some use cases (eg. multiple references to the head node and the head changes), but even this object would only have the information about the head node.

@leetcodeking4859 Жыл бұрын

Love the hair!

@seandougherty3022 Жыл бұрын

I'm going to speed run 3 problems of increasing difficulty. also I wrote these problems sooooo..... nice :)

@nithishthomas1514 Жыл бұрын

In Q1, Wouldn't creating a visited matrix create a space complexity of n? Maybe replace 1s which are visited with 0?

@JitendraSingh-qd7jk Жыл бұрын

Stop with that dynamic programming.

@sansai9329 Жыл бұрын

we can replace 1 with 0. it would work. but sometimes the interviewer asks not to change the input array.

@alex.does.comedy Жыл бұрын

It was Q2 but I was thinking the same thing. Toggle the 1s to 0s and you should be good to go. Complexity remains the same though. However under heavy space restrictions a constant in the complexity can still influence your end result.

@alex.does.comedy Жыл бұрын

@@JitendraSingh-qd7jk that's not dynamic programming though

@Sportsandgames6 Жыл бұрын

@@sansai9329 that makes sense if the interviewer asks not to, but I'm more confused as to why the optimal still says O(wh) instead of O(1)

@anand.prasad502 Жыл бұрын

I have algoexpert subsription but it's not giving me autocomplete Clement

@abudhabi9850 Жыл бұрын

Clement, any hair color suits you, so jealous since I am bald 🤣

@shubh13799 Жыл бұрын

Still you have excellent coding mindset

@Rahularity01 Жыл бұрын

32:26 When you shift by k...you will find a gay.

@subham-raj Жыл бұрын

Last problem doesn't seems like a hard one. Even the second one is just easy to medium :)

@OogaBooga3806 Жыл бұрын

The blonde hair is cool 👍 not that you need it, but it has my stamp of approval.

@samirzafar Жыл бұрын

Throughout the whole video and all of the problems the one thing that I can't answer is.. why isn't Clement using the pc in the background.. ?

@richarmelo1958 Жыл бұрын

you should do some codeforce

@AhirZamanSairi Жыл бұрын

Something's definitely different, just can't put my finger on it. Oh, new v neck perhaps.

@sansai9329 Жыл бұрын

for 3rd problem, will this approach work? if k is positive, reverse the linkedlist, move first k elements to tail, reverse the linkedlist again, and return head. if k is negitive, move first k elements to tail, return head; if k = 0 || k == length return head;

@Nooop655 Жыл бұрын

Your way does not work at all. I am assuming you are a new programmer because your way is horribly wrong. I hope u get better. I wish u the best of luck.

@yasinnkhann Жыл бұрын

@@Nooop655 bro what’s wrong with you?

@JacobAuthier Жыл бұрын

Try it and let us know

@loop4303 Жыл бұрын

His hair color changes every 2 months. He will soon reach Ultra Instinct.

@TheWizardEngineer Жыл бұрын

Good hairstyle, clement !!

@valbonite5389 Жыл бұрын

Straight from that baseball scene in Twilight I see

@akashmore83386 Жыл бұрын

Upload solution on algoexpert in Javascript

@Kshitij-fw7bh Жыл бұрын

Clement is on ssj1 level. Although he reached god level 1st.

@NickHamilton88 Жыл бұрын

Clement is the main character

@amospan14 Жыл бұрын

Super Saiyan 2 confirmed! =D

@rishabh7762 Жыл бұрын

Nyc look Clement 🔥

@lifeofme3172 Жыл бұрын

Next year he will go into super saiyajin mode with a ponytail 😂😂

@megadeth_9611 Жыл бұрын

Your hair 🙂 Super Saiyan let's goo

@joevandevusse3004 Жыл бұрын

Hair looks good!

@AlShahriar10 Жыл бұрын

New hairstyle (alone with new color!) :')

@LuminarySports Жыл бұрын

I love your tutorials but Algo expert makes me look dumb

@curlymike Жыл бұрын

Duuude, this blond hairstyle is so dope!

@CleverCpp Жыл бұрын

for the software engineer it is not nessicare to use language programming to solve the problem I can use the javascript interview ?????????!!!!!!!!!!!!!!!!!!!!!!!!!!

@PierreDennis Жыл бұрын

Want to make these really difficult Clem...write it in PHP!

@alex.does.comedy Жыл бұрын

I tried the last problem also and my solution looks like this function shiftLinkedList(head, k) { let curr = head; let length = 1; while (curr.next !== null) { curr = curr.next; length++; } curr.next = head; curr = head; for (let i = 1; i < length - (k % length); i++) { curr = curr.next; } head = curr.next; curr.next = null; return head; } Took me about 15 minutes. While you count the length when you're on the last element you can make list cyclic. After this one iteratation you can skip ahead length - (k % length) positions and set the next node of the node you landed on as the head and the one you landed on it's current to null. So basically you make the list a closed loop, then break the look at length - k.

@Nooop655 Жыл бұрын

This doesn’t work. There are some syntax errors and logical errors. Idk if u want me to point em out.

@alex.does.comedy Жыл бұрын

@@Nooop655 please do, I love a good code review. Btw. the code passed all the test cases.

@Nooop655 Жыл бұрын

@@alex.does.comedy Interesting. You could’ve done it a bit more efficiently. Should I explain.

@alex.does.comedy Жыл бұрын

@@Nooop655 don't hold back. conversation is what makes engineers better ;)

@alex.does.comedy Жыл бұрын

@@Nooop655 although it's O(2*n) === O(n) time and O(1) space complexity so I don't really see how we can make the whole thing more efficient. Really excited about your optimization!

@kr4k3nn Жыл бұрын

Clement, when you mastered Ultra instinct?

@anshumansingh9184 Жыл бұрын

Blue is next, right!?

@milesroyer172 Жыл бұрын

Clement looks like the dad from megamind

@theory5810 Жыл бұрын

For the medium question, Clement's DFS traversal function looks like it'll return early for the and give the incorrect answer for the following: [11111110000] [00000000000] [00000000000] [00000000001] Can someone explain why it doesn't? To me, his function will start at the top left corner, which is a 1 in the above example, then look DOWNWARDS. Since the cell in the next row down is a 0, it'll return early, effectively ending the loop.

@Wodro Жыл бұрын

It will end one branch of recursion, the downwards neighbor traversal. The horizontal neighbor traversal will still continue

@lequdindoquede78 Жыл бұрын

Mastered ultra instinct

@ClipForShort Жыл бұрын

Hair looks fire on you

@nashetali2348 Жыл бұрын

Clement, wow great video. I must appreciate. Requesting you to please, could you please provide me an opportunity for a mock interview on your channel.