LeetCode Exercise in Java Tutorial - Two Sum FAST Solution

[@danielaviv8215]

Please do this kind of videos more!

[@jerryfan4067]

I second this

[@AAfzal5]

I third this

[@TheTucsonstoner]

Fourth!

[@BrotherV07]

Fifth

[@pngexportimport]

This looks like an array, so I 5th this lol

[@BlazingStar2001]

Doing more these kinds of things is very helpful, especially how u approach them. Teachers normally tell us the optimal solution but how to get to that or how to come up with that solution is not normally taught to us.

[@manosmakris8308]

Do more of these kind of videos because your thought process make me think in a different way than before.

[@wadebrumbaugh7579]

I thought of your initial solution right away but would have NEVER thought of the better way. These types of videos are EXTREMELY helpful in reprogramming the way I look at a problem. Thank you!!

[@maaax573]

Comments like this help me understand that its ok that I couldnt come up with that second solution on my own. Thank you.

[@memesv3.093]

Thanks a lot John. Please start a Leetcode series, your way of explanation is flawless

[@omarkabada2923]

Yes, more videos like this would be amazing because you don't only solve the challenges, but explain the thinking behind it.

[@MohitKhare]

well said sir ! Even I can understand the concepts quite easily and I'm not a native english speaker.

[@zoflax]

honestly a weekly leetcode video like this would be so good. Please do more!

[@Riv3rt]

Love these algorithm video's personally, keep'em coming! Of course all your tutorials are also awesome- so I guess just keep up the good work!

[@RizwanAli-by4nl]

Please do this kind of videos. It helps alot to understand the problem

[@GuessWhos]

Please, keep doing this leetcode content. There is not good leetcode videos in Java, so this is gold!

[@محمد-م5ث1ش]

We want more leetcode questions! you're an expert in teaching. Thanks a lot.

[@Michaelpschreib]

As a mostly self taught dev, I really appreciate your content. It has helped me grasp concepts I've been struggling with for a very long time. Thank you!!

[@MatthewWeiler1984]

Great solution. You can decrease the memory footprint by not bothering storing the complement/index of values that are greater than the target as those would require negative numbers to achieve the target.

[@tonypsilon_gaming3221]

Well, the problems only states integers, so they might as well be negative, or?

[@MatthewWeiler1984]

@@tonypsilon_gaming3221 Fair enough. But 1 question that I would ask is if negative numbers are possible in the source array. But since this is an online test, which can be submitted multiple times, I'd assume as much and run my answer to see if it fails any test cases... If it passes all test cases, then I would add a comment explaining the optimization.

[@joryroberts2518]

More of these types of videos would be fantastic! Your explanations throughout all of your videos are incredible, and I just started tackling coding challenges and I've been struggling with how to even begin. Appreciate your channel so much!

[@christianolsson8644]

I definitely want more videos like this! You're an excellent teacher. I'm trying to get a job as a Java developer and I'm freshening up my knowledge. I will always come back to your videos. They are fun, interesting topics, easy explained and very helpful! 😃

[@Ольга-ж5к4й]

If you struggle with finding a first job, try to look for testers, then get to automate tester, then you will be a perfect java coder because you know how stuff should work. Requirements for junior tester are so little, it is easy to apply

[@soniahandle]

A playlist with videos like this would be phenomenal! Thank you for sharing these with us!

[@hinocenciopaulo]

Dude!! Thanks a lot for this video!! I was straggling with this same question in the AlgoExpert, and I couldn’t understood the Clément's explanation. You explained SO MUCH better, and for free... Please launch a course of Algorithms and Data Structure. I'll definitely pay for that.

[@chair_force]

Yes more leet code/algo videos, there’s barely any good Java leet code videos on KZbin. Mostly just python and JavaScript videos. Java is neglected on leet code.

[@nabeelrehman5451]

Was just solving this problem and your video came in. Thanks and would love to watch more videos on leet code problems.

[@musaddiqmanzoor2044]

I've to advocate that we do need more such stuff, @John.

[@stefans6557]

From what I know first solution is: O(n*(n-1)/2) and for the outer loop you should do: for (int i = 0; i < nums.length - 1; i++) Of course it still can be simplified to O(n²) - but never really understand why. I mean it's quadratic, but still quite a reasonable difference to loop i and j from 0 to end. (about half the time of O(n²), which I think is still a difference, especially if it is longer, like from 20 mins to 10 mins)

[@santiagoaristi2808]

Thank you John for taking the time in creating this video! Please do more of these videos as it teaches problem solving skills and how to walk through the creation of an algorithm. Thanks!

[@DevSofo]

So happy i found your channel...😎 premium value ✌️✌️✌️

[@tangobee]

really this is soo awesome because i just started doing leetcode and i wanted someone who can guide me and here you are like a angel :D

[@neeldiyora3575]

I'm new to this channal. Before I saw this video I don't knew what is really hashmap is but after seeing this..... Nothing to say. This video is really helpful. Thank's for creating this awesome video.

[@anthony68759]

All of your videos have been so incredibly helpful to a career changing CS student like myself! Leetcode has always seemed super intimidating but your teaching style really makes them seem doable. Please do more like this!

[@javo_rocker]

That's a great video! I had had struggle finding a solution for that kind of problems and that helps a lot. Thank you so much!

[@kevin_mitchell]

9:44 The solution will return [2, 2] for a target off 8 which is incorrect since the same element is used twice. The code for the "i" should be for (int i = 0; i < nums.length - 1; i++) {...} For the i, j loop version.

[@SailBuddha]

Never thought about a solution like that before. This is a very useful tool to add to the tool box. Thanks!

[@esmelealemmihretu941]

Please we need such kind more questions! Appreciated!

[@NandanChhabra91]

Thank you for covering such problems and that too in detail. We usually don't get such insights when doing things alone. Please park some time for adding such videos regularly. Thank you

[@jatinkumar7287]

Plz do this more often I'm learning java so it's very helpful on how to approach leetcode problems. Thanks.

[@micleh]

In order to create a stash of solutions to common problems, I'd love to see more of such videos, taught by someone who really knows what he's doing and who can teach in a clear and straightforward manner. Thanks for sharing this knowledge.

[@andrewchang7194]

Two sum was my first experience to how useful hash maps were. Started using them in all tasks where you need to look at every unique element of an array.

[@santhoshkumar7285]

Do a lot more videos like this!!! I love The way you explain it, keep doing this

[@amaralensheriff]

I had to rewatch the last section as you suggested to finally get it, thanks again John. You are the man.

[@SrikanthNalla17]

Yes Please add more videos of leetcode problems

[@davidzurawski4243]

Please do more of these leetcode videos!

[@CodingWithJohn]

The most recent video is another one!

[@applemaysl]

Can you please do more of these? Your explanation was so clear and to the point, I wish there was more!

[@Andboldquates]

thank you solving problem with deep details, we having mostly trouble to understand , the way how you explain is highly catchable

[@TheNameIsAdmiral]

One of the best coding channels. VERY well explained. Cheers! You deserve way more subs.

[@sarojmaharjan3986]

Wow do more of these videos ! Love your explanation

[@pliegosevilla]

Im so grateful you are doing this. You are one amazing teacher. It’s so easy to understand code with your explanations. Very very grateful.

[@UTJunaid]

Please do this kind of video more and more! your explanation is so easy to understand. I got the concept in the first watch only.

[@debasishpradhan9951]

Hi John , waiting for the next episode , it will really help to broaden the logical thinking . I'm a java developer, but never imagined hashmap can be used in such a way.

[@pejko89]

Simply amazing channel. Gives me so much confidence to keep learning and not to give up.

[@martinnnachi]

Would definitely like to see more challenges! Never would've thought about using a hashmap and like you said, one more thing I've learnt. Thanks a million. You're a great teacher!

[@narenm.s8923]

Please do these kind of videos.. because of your great explanation about hashmap now i understood it.. Before i know what is a map, set but i don't know how they actually work..now i know Thankyou

[@andreuzamurengera848]

This solution is amazing. We would love to see more questions of this complexity

[@mohsenrezaee9936]

That thing you said at the end... That makes me feel so much better about myself. I used to feel like there's something wrong with me, but it's natural, apparently!

[@gurudattshahane]

Please make more videos like this, your explanation is just amazing💞. I am grateful to have people like you delivering high quality content free 🙏🙏🙏

[@EstrellasBakery]

I really appreciate the message you start to give at 21:57 - I have been feeling very discouraged as of late trying to sharpen my problem solving skills and it was very comforting to hear that. Thank you!

[@noahdavis3663]

i really like how you showed two different implementations

[@akshaynile2778]

Wow ! Really a brilliant solution using a Map. 😇 Thanks for this video John. I learnt a new technique today. 👍

[@shariefrana]

Love the way you teach and present the content in most simplest way, It would be great to see DSA and System design courses from you.

[@Bladebreak3r]

Thanks for the encouragement at the end. My solution is close but not quite optimal. It's O(n) space complexity but O(2n) time complexity. I felt bad about not thinking about the hashmap solution until you gave your encouraging words at the end! Thanks man 🥺

[@harika2988]

Really like the way you have presented the logic and would like to see more of these kind of videos.

[@aspeno5613]

thanks for your thorough explanation of the hash map! I understand it so much better now!

[@nanthawatanancharoenpakorn6649]

Please do more. I would like to learn and see how you approach the problem, why you think and how you think.thank you

[@oleksandrkardash4898]

please make more of these exercises! This is a good way to learn and practice coding

[@mehmetakif8639]

Well, i think i can watch these kind of videos whole day without getting bored. Well done. Just perfect.

[@sultangaddafi8698]

I was stuck for hours looking on how to write the first line of code on such leetcode problems....leetcode can be intimidating but thanks for such content, it really helps!!....please do more especially in java

[@hassansiddiqui8231]

I have to agree with the majority of the other comments - your explanations of algorithms for solving LeetCode solutions (well, in general good software algorithms) are some of the clearest I've seen. This is probably going to be a new subcategory of videos that you might not have planned to do, but I can see there's so much interest you have no choice but to do them! (Please?)

[@a1esandra]

I really needed to hear that last bit in the end. im a 2nd yr cs student and ab to do my first technical test for an internship n i find them very hard and even thought of dropping out lol. so thank you

[@randomname6444]

This did kind of blow my mind ngl. I would've never thought of this solution to the problem. Now I wonder where else this method might be applicable.

[@richardmeyer418]

Thank you. This was super interesting (to me, anyway). Please give us a few of these every now and then - I'm not asking you to make it exclusive, but it was fun.

[@ibrahimwadi6539]

OMG!!!!! man how can you be so good at teaching ??? you just made my day. please keep the videos coming 🙂

[@minakianrad812]

Thank you for this video. Please do more of the Leetcode problems. Thank you.

[@upzaiz8095]

Yes.. Nice. Coding is not just getting the correct result. But it also getting the result in correct/optimal way. Please deliver this type of videos which really brain storm and change the thinking way of coding.

[@fojirngers3661]

I don't get it, why people don't subscribe and like this guy's channel and videos. He is the best.

[@talk9415]

please stop, you have some very good java vids, super useful. for any leetcode question you can find million solutions.

[@lanatimmo3686]

Thanks a lot for this clear explanation! Please, do more tutorials for LeetCode exercises!🙏

[@UHealthyLife]

please do more videos like this. your channel is more helpful for beginners too.

[@sdors4]

You have a brilliant mind, that’s so simple solution and very smart

[@rafaelmarcos9733]

Thank you, I was struggling on how to optimize my solution in C using just One for loop.

[@JRC.40.31]

It took me a week to "sink in " but I solved my first leetcode with this video , thanks God this video Exist and Thank you John for creating such an amazing video .

[@grimsri3782]

Please post this kind of videos more. I like the way you explaining the details by going into the deep. I am waiting😋

[@SHIVAGARCÍACHUMKHWAN]

I love the way you explain these things!

[@auniquehandle]

Hi John, i love this video. Learning algo on Leetcode is hard even with looking at the solution. However this video helped me understand 2 sum very easily. Thank you

[@nandhurix9547]

Hi John, the way you explained is more clear and more precise so I suggest you do this kind of video more and make it a playlist for Leetcode easy problems, People who are new to Leetcode like me would appreciate more content like this.

[@fortuneblaise4832]

Please make more algorithm problem solving videos. It is really helpful. Thanks John!!

[@MohitKhare]

My freaking God John, that was the best explanation I've found so far on the internet. Sure there could be more ways but the fact that you are able to explain it so easily and also the way you communicate as a speaker is remarkable. Keep doing what you do buddy, and thanks a lot. ❤ from INDIA. I feel blessed that we have people like you working with JAVA.

[@tfamidoinglol4243]

Please make more of these videos. This video was very well explained.

[@CodingWithJohn]

Thanks, I plan to!

[@WealthyFrog]

you are awesome man! You've given me a new way to face problems like these! Thank you.

[@Raied114]

I'd love to see more videos about what you talked about at the last min of the video: "I never would have thought of that!". Your way of explaining the thought process is exactly what I'm looking for in these types of videos. I don't just want to see the solution to this or that coding problem, but the idea behind it. Please keep them coming!

[@faizquazi292]

That's awesome John, really helped watching you code with that simplicity and understanding....♥️♥️♥️

[@davidx5828]

Really good video, explaining the code was in-depth and at an appropriate level. Maybe a video on the time/space complexity? That was a hard concept for me starting out.

[@levybuildz]

Just started my Leetcode journey and this was the exact video I needed to feel more confident about trying more problem and being ok about not knowing the best answer or an answer at all. You thoroughly explained 2 ways of solving the Two Sum problem and reassured me that practicing more leetcode will sharpen my eye for finding solutions to coding problems. IMO this is a must watch for all first time leetcoders! Thank you John 🫶

[@dele1518]

Please do more like this. this is really awesome

[@kingjames8723]

Hey John, Thanks so much for your videos they have being really helpful to my java knowledge. I would love to see more videos from you on Arrays, OOP and Real life application of Arrays and OOP. Thanks a million. Big thumb 👍

[@sebon11]

Dude this video is brilliant and excellent! Not just the solution, the explanations and the speech at the end as well. Thank you!

[@Molotom]

Great video, John! What sets you apart is that you have a very clear communication style, and you're very encouraging as well. I think that this LeetCode video showcases those skills really well, and it would be awesome if you made more in the future :)

[@jvjohn]

Thanks John. This was very helpful. Please keep adding more of these kind of videos.

[@CodingWithJohn]

Glad it was helpful, I'm planning to!

[@gabrielmaga970]

Thanks a lot John. Please start a Leetcode series.

[@amitborkar6345]

Yes Please! keep the leet code videos coming.... I love the way you explain things.

[@kareemlateefyomi8690]

Thanks John, this puts a smile on my face. Hope to see more of this

[@ShakilaBoler-wz1os]

Hey John please do more leetcode videos. I love how clear and precise your explanations are!! I was sad to only see the two videos in the playlist. Hope you’re doing great!!

[@ThinkScienceCanada]

this video is amazing!! thanks for all the explanation, please continue with this! Im using java to do these code challenges and your videos helps me a lot

[@alakerejenus8993]

This just opened my brain up.

[@ankur5648]

Please John keep them coming I'm a university 3rd yr student and tbh I would have never been able to out that approach. I don't know when i will be able to think like other programmers 😩