How long until you were "proficient" at leetcode

Appriss rRkU55
Nov 13 25 Comments

Please don't poison the well with "I did 5 questions and got L5 at google".

I'm on month 2 of LC with about 50 questions complete. However, I don't think I'm prepared for an interview. At what number did you begin feeling confident in your ability to solve within 30 mins.

Bonus points if you've got any tips to help with avoiding silly mistakes like out of bounds indexing and off-by-one logic errors.

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TOP 25 Comments
  • Rally Health undead
    Did 120 in a month, mix of easy/medium/hard. Never felt 100% comfortable, but got FB/G offers regardless. Remember: the way in which you practice matters more than how much you practice.
    Nov 13 11
    • New / Eng ronney
      Can you please tell us how you prepared for system design?
      Nov 14
    • Rally Health undead
      Sure thing. The best thing to know to game the system design interviews is to remember the pneumonic "CLAD HDS" which is the order in which to go about a sys design problem.

      1. C = Clarify requirements/features. Ask questions regarding inputs and outputs and what you need to actually do programatically. Make sure you know the question being asked, restate it in your own words and ask the interviewer if what you said makes sense.
      2. L = Load estimation. Do the math on how much load/bandwidth/data/etc you'll need per component and talk this out with your interviewer to know if you're on the right track.
      3. A = API. Discuss the policies and API you intend to have in place and how you would implement them.
      4. D = Data schema. Draw/write out the classes/db-tables that you plan to use/implement and explain how they related and how they're necessary, etc.
      5. H = High level architecture. Draw out, at a very high level, the components you need. Datastores, load balancers, servers, etc. There is no need to dive into detail at this stage unless they prod you for it, in the interest of time.
      6. D = Detailed component design. Now it's time to drill into each component (ask your interviewer if there is any component they would like to drill into, so that you arent drilling randomly) and hash out specifics.
      7. S = Scale/Single points of failure/etc. Now, it's time to identify how you'd make your system better, identify the single points of failure and how you'd remedy them, how you might partition data for parallelism etc. Your interviewer will likely ask you this regardless but taking the initiative to answer preemptively is a good signal.

      So that's the meta-"how to do the system design interview." For practice, the best is, of course, real life experience in doing architecture and system design/implementation, but after that "grokking the system design interview" on educative.io is good. And I youtube'd some examples as well. (there is also "system design primer" - I've heard it spoken about in good regard, but I have no personal experience with it)

      In my case, I had previous experience in this area so learning the meta of "how to go about the system design interview and what they're looking for" was more important.

      EDIT: Also important to know is that they sys design interviews are super-conversational. Just imagine you're designing a real system with your team. There would be a ton of back and forth, so try to mirror that with your interviewer by pretending he's a teammate that you're hashing ideas with. You should be driving the discussion but pinging off them constantly to see if you're on the right track. A good split of who talks is 70-80% you, 20-30% them.
      Nov 14
    • New / Eng ronney
      Makes sense. Thanks for your response!
      Nov 14
    • Rally Health undead
      Np!
      Nov 14
    • Apple bogle
      Can you talk more about how you did spaced repetition? After how long would you come to the problem to solve it again? And how many times?

      Like what were the intervals like?
      Nov 14
  • Cerner toolplex
    You'll never be as confident as you want to be for interviews. That being said 150 is a good point to start interviewing.
    Nov 13 0
  • Quality over Quantity!
    Nov 13 0
  • To avoid silly mistakes, go over your code with an example input
    Nov 13 0
  • Facebook / Eng cat++
    300, 6 months, got me to a FAANG
    Nov 13 0
  • Google PCBro
    Never
    Nov 13 0
  • Amazon odh79ebB
    Been ~6 months and just starting to. Not a rigorous 6 months. Couple problems/patterns a day with bursts here and there
    Nov 13 0
  • IBM / Eng ieatcode
    I did about 84 in roughly a month span (so about 2-4 a day after work or so) before my L5 onsite for Amazon and breezed through the technicals (IIRC it was 2 LC mediums and 1 LC hard). I got rejected because they felt my LPs didn't show that I had enough work experience. I'm less than a year out of school as a new grad but I thought that was pretty dumb since they can clearly see my total work experience on my resume. I'm definitely not proficient to the point where I can easily solve a LC hard without help and it still takes me a bit of time to solve most of the LC mediums, but after a while you start to see patterns that can easily be applied for other problems. Things like graph or tree traversing using BFS, Kadanes for contiguous array sub problems, two pointers for two pointers problems, etc you definitely start to notice these solutions quicker.
    Nov 14 2
    • Apple bogle
      Any luck with other companies? That ~1yoe spot is tough b/c you are too experienced for new grad and not experienced enough for everything else

      Also, do companies ever ask about your personal projects listed on your resume when you interview?
      Nov 14
    • IBM / Eng ieatcode
      It actually worked out because I used the time window of waiting to hear back to negotiate a salary with a start up with close to the Seattle salary (factoring in col). They didnt ask me specifically, but I used my past experiences with projects and hackathons to answer some of the LP, but I think they were looking for people with more industry experience. They said to apply again in 12 months and I'll have it in the bag, but we'll see.
      Nov 14
  • Pure Storage CiLh06
    120+
    Nov 14 0
  • 3-6 months if you treat it seriously
    Nov 13 0
  • Google rjMH13
    200
    Nov 13 0

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