I am an ex-googler who's ranked in the top 200 worldwide on LeadCodeContests,
a live stream lead code, and answer questions from junior engineers almost every day.
Here are my thoughts on how to get good at LeadCode.
I'm new to algorithms, how do I learn this stuff?
The short answer is, don't read books, start by doing lead code problems.
You might ask, how do I pick up the theory, how will I know which algorithm to use?
The simple answer is, you pick it up as you go.
you try a and you either solve it, congratulations, or you don't, and then you have to go back and look up the solution.
Every problem has excellent in-depth solutions that will,
over time, bit by bit, introduce you to all the concepts you ever need to know to get good at leadcode.
There are thousands of problems.
How do I know which ones to solve?
If you're not sure where to start, pick from a small curated list, like Blind75 or Needcode Roadmap.
If you do have a particular topic you'd like to practice, go to the problem list and filter by tags.
Leadcode has tags for virtually every technique covered in algorithms interviews.
One final note about difficulty levels.
You should try to pick up problems that are just outside your comfort zone.
For example, if you can comfortably solve ez's, level up and try a few mediums.
Trust me, it pays to adopt the mentality that you must consistently challenge yourself in order to succeed.
I recommend spending about 30 to 60 minutes struggling with the problem.
Then, if you're still stuck looking up the solution.
If you spend less time than that,
I find that you don't really give your brain enough time to dig through your toolbox of techniques and logically put together a solution.
And that's like the fundamental activity that enables you to get better at this.
What types of problems do I need to be able to solve to get a job?
As always, this varies by company, job type, and location.
For example, on average, back-end will typically get slightly harder algo questions in front-end, and fangs will be harder than startups.
Some countries have very lead-code-centric cultures and tend to ask a higher quantity and difficulty of these types of questions.
For more senior positions, specialized experience and system design matter a whole lot more than lead code.
They might not even ask any lead-code questions.
That said, in the US, for a junior software engineer job, I'd say try to solve easiest comfortably and maybe a few mediums.
In terms of topics, study at the bare minimum.
graphs, and dynamic programming.
For fan companies, you'd probably want to bump that up to at least comfortably solving mediums.
Again, this opinion is purely anecdotal, varies greatly across companies, and is subject to change over time.
Do I need leadcode premium?
No, in fact, the premium problems are actually less valuable than the free ones because they're often fewer user-generated entries in the Solutions tab.
Often, the company tags you see with premium are outdated and many of those companies explicitly
stop using problems that appear on websites like leadcode, completely defeating the purpose.
On a broader note, the same advice goes for anyone trying to sell you anything.
When it comes to leadcode,
anything you have to pay for is basically stuff you can easily find for free, slap together in some sort of guided pattern.
Whatever it is, you don't need it.
Okay, so what if you're a visual learner and you like detailed video explanations?
Well, if you need a video explanation for every problem, just type lead code problem number in YouTube.
And no matter what problem it is, you'll find plenty of high quality videos.
Now, if you have a sharp eye, you may have noticed that I personally have premium.
And that's for exactly one reason.
I do live streams on Twitch,
and viewers often ask me to solve lead code problems, some of which are pretty I struggle with solving problems under a time limit.
The boring, but correct, answer is, practice under an actual time limit.
Lead code virtual contests are really good for this.
You get 90 minutes for four problems.
Don't worry if you can't get all four or even have trouble solving one.
The whole point is to gain experience doing problems while dealing with There's also a great new tool called Lead Rooms.
It's a completely free Chrome extension that simulates a four-problem lead code
contest with friends where you also get to pick the topics and difficulty levels.
I find both of them really fun.
We do lead rooms almost every day on stream.
Additionally, every Saturday right after the main weekly lead code contest, I go over solutions to all four problems.
useful to you, the stream link is in the description below.
Do I need to learn Python?
I know another language, but I heard it's easier.
I would say, if you're comfortable in the other language, definitely use that one.
If not, Python does have a few advantages for algorithm interviews, shorter syntax, no types, and loads of syntactic sugar.
More importantly, when something goes wrong, it's generally easier to debug.
Those of you who work in C++
know that the last thing you want to see in an interview is a program that outputs nothing but the words segmentation fault.
