I have been solving LeetCode problems since June last year. After over 9 months of dedication, I have solved 400 distinct questions. But getting to this point wasn’t easy. In the beginning, I struggled to find the right approach to LeetCode and often felt stuck.
There are several study plans available, and as some bloggers suggested starting with LeetCode 75, I followed that plan. I couldn’t even solve an easy question. Sometimes, I had to find a video or blog for explanations and attempt the question without looking at the solution. I struggled with many new techniques that I had never used in my career.
After a couple of weeks, I felt that I couldn’t keep up with LeetCode 75 as the problems were too difficult for me. I looked for alternatives. That’s when I noticed the LeetCode daily challenge.
Each day, a question is selected by LeetCode staff, usually covering a particular topic for several days across all difficulties. I found this approach effecive as it felt like progressive training. Therefore, I started solving the daily challenge every day. As of today, I have collected daily medals from Oct 2024 to Feb 2025.
Full disclosure: I used a couple of time travel tickets.
One of my daily metrics is to solve at least one LeetCode challenge every day. This metric applies when I’m travelling. During my recent trips to Japan and Scotland, I solved LeetCode problems after returning to the hotel. In the past 290 days, I only missed 2 days.
Solving daily challenge wasn’t enough. I also needed to improve my approach to problem-solving. I then (re-)learned Data Structure and Algorithms. Thanks to the advance technology, there are now plenty of online resources.
Data structures by WilliamFiset
Many new learners overlook the power of sketching ideas. I did too, until I started learning dynamic programming last October and realised its value.
What you have in your head, put down on paper. The head is a fragile vessel.
– Dmitri Shostakovich (TBC?)
Sketching ideas is a very effective in learning technique. When solving conceptual problems, it’s difficult to keep everything in your head. Your brain functions like an LRU (Least Recently Used) cache – with limited short-term memory, some details will be pushed out when you try to process new information. Sketching ideas frees up mental space, allowing you to focus on more complex concepts.
I began drawing diagrams whenever I felt a problem wasn’t trivial. I went from feeling stuck and unable to code anything to sketching something useful. The drawings might not always represent the most efficient algorithm, but at least they helped me explain the problem and lead to the solution before thinking of optimisations.
Recursion drives me insane.
Another suggestion is to watch solution videos even if you can solve the problem and optimise it. I always watch NeetCodeIO’s videos after completing the daily challenge. This exposes me to alternative approaches by understanding others’ thought processes. For example, you might solve a dynamic programming problem using a top-down approach, while someone else uses a bottom-up approach. Learning from these differences broadens your perspective. A bonus is getting exposure to other programming languages, such as Python, which I’ve never used before.
I recently started the NeetCode 150 study plan, revisiting problems I solved over 6 months ago. This time, even the hard ones felt easier. Of course, that doesn’t mean I can instantly solve any problem thrown at me. Sometimes, I still have no idea where to start and need to look for hints. However, throughout this process, I have learned many techniques and gained confidence in tackling difficult problems.
My friends warned me that solving LeetCode problems doesn’t guarantee a job offer. Of course, I knew that. But LeetCode is no longer just a job-seeking tool for me. It’s like Wordle or Nonograms. Just as Mahjong helps elderly people prevent dementia, LeetCode keeps my mind sharp. Whether it helps me land a job or not, I’ve already gained something valuable from this journey.