LeetCode
The largest practice problem archive, with a built in judge, community solutions and contests. It is a drilling ground rather than a curriculum, so bring a plan or you will wander for months.
Platform
Interview Prep
LeetCode
Ongoing
All
Free
What it is
The default coding practice platform, with several thousand problems, an online judge, discussion threads and weekly contests.
What it is good at
Volume and feedback. When you know exactly what you need to practise, the archive has it, and the judge removes any argument about whether your solution works. Contests are the closest free approximation of solving under time pressure.
Where it fails people
It has no opinion about what you should do next. Left alone with it, most people solve easy array problems for two months and conclude they are preparing. Pair it with a curated list or a roadmap and it becomes excellent.
How to use it
Bring an external list, use the tag filters to drill weaknesses, and read the top discussion answer only after you have a working solution of your own.
Best for: the repetition phase, once you already know what you are practising.
Ready to start?
Opens on LeetCode in a new tab.
Stuck on something specific?
Writing only gets you so far. If you want an answer to your situation rather than the general case, book a session and we will work through it together. Every session is free; a few slots open each week.
Follow along
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