15 Coding Patterns You Must Know for Interviews

15 Coding Patterns Which can be used to solve 100+ Leetcode problems

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If you have prepared for coding interviews then you know how daunting it can be. Apart from the regular work you do, you need to spend a considerable amount of time practicing data structure and algorithms problems just for the interview.

I have done that, but more often than not, it's either miss or hit.

If you get the coding problem you have practiced then the interview can be a breeze, all you need to do is act as if you are solving that question first time – but if you get a really unknown question, then good luck to you.

I knew my interview prep approach wasn't foolproof and needed improvement.

After solving so many problems, I noticed certain tricks, or patterns, I could apply repeatedly – for example, how the Two-Pointer technique on a linked list can help find the middle element or detect any cycle.

I didn’t know that these are essential coding patterns until I came across Grokking the Coding Interview: Patterns for Coding Questions course from DesignGurus.io. This course teaches you 24 coding patterns which can be used to solve thousands of LeetCode problems.

That’s the first time I came across this terminology and also learned many other patterns I didn't even know.

Just knowing that helped me a lot in my coding interview prep and also to many of my readers who thanked and appreciated me that I told them about these patterns and this course.

In this article, I am going to share 15 coding patterns you can use to solve 100+ coding problems. Many of them are also covered in Grokking the Coding Interview Patterns course on Educative, in greater depth.

Now, you don’t need to blindly solve many coding problems just to get your hands on it. Instead, learn these patterns, and then start using them to solve problems.

To make your preparation structured and effective, I also recommend Grokking Advanced Coding Patterns for Interviews from Designgurus.io. This course covers more advanced coding patterns you need for interviews and integrates interactive practice.

Educative also just rolled out AI-powered Personalized Interview Preparation Plan. Think of it as a custom prep roadmap, tailored to your strengths and gaps.

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15 Coding Interview Patterns Every Developer Should Learn

Without any further ado, here are the 15 essential coding patterns you should master, along with 2-3 Leetcode problems to practice for each.

1. Two Pointers

Two Pointers is a versatile pattern that involves using two pointers to traverse an array or linked list efficiently.

This was the first coding pattern I learned and it works remarkably well on solving linked list and array based problems like finding the middle elements of the list or finding the kth element from the end of the list.