Don't Just LeetCode: Why Grinding Problems Fails

Coding Interviews are getting harder to pass. To prepare for coding interviews, you will need weeks, if not months of preparation.

No one really likes spending that much time preparing for the coding interviews. So is there a smarter solution?

First, let’s look at the problem.

Anyone preparing for coding interviews definitely knows LeetCode. It is probably the biggest online repository for coding interview questions. Let’s take a look at what problems people face when using LeetCode.

Problems with LeetCode

There are more than 2k problems in LeetCode. The biggest challenge with LeetCode is its lack of organization; it has a huge set of coding problems, and one isn’t sure where to start or what to focus on.

One wonders, is there an adequate number of questions one should go through to consider themselves prepared for the coding interview?

I would love to see a streamlined process that guides me and teaches me enough algorithmic techniques to feel confident for the interview. As a lazy person myself, I wouldn’t like to go through 500+ questions.

The Solution

One technique that people often follow is to solve questions related to the same data structure; for example, focusing on questions related to Arrays, then LinkedList, HashMap, Heap, Tree, or Trie, etc. Although this does provide some organization, it still lacks coherence. For example, many questions can be solved using HashMaps but still require different algorithmic techniques.

I would love to see question sets that follow not only the same data structure but also similar algorithmic techniques.

The best thing I came across was the problem-solving patterns like Sliding Window, Fast and Slow Pointers, Topological Sort, etc. Following these patterns helped me nurture my ability to ‘map a new problem to an already known problem’. This not only made this whole coding-interview-preparation process fun but also a lot more organized.

Coding patterns enhance our “ability to map a new problem to an already known problem.” For a list of coding patterns, check Grokking the Coding Interview.

What to Do Instead

Stop measuring progress in problems solved and start measuring it in patterns recognized. I have gathered around 20 of these problem-solving patterns, and once a pattern is familiar it unlocks dozens of problems at once.

The full catalog lives on its own page: all 20 coding interview patterns, each with a description, the situations it applies to, and example problems. For the LeetCode-framed view, meaning which patterns return the most against the actual distribution of LeetCode problems, see our guide to LeetCode patterns.

The coding courses are one track of a larger series. The Grokking course series page lists every course with the level it is written for and which one to take first.

Here is a short intro to each pattern with sample problems: