20 Essential DSA Patterns
The 20 core coding patterns behind most interview problems. Master these and recognize the shape of any new question.
By DevsUnite · 180 Problems
Total Problems: 180Difficulty Levels:EasyMediumHard
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Frequently asked questions
What are the 20 Essential DSA Patterns?
A curated set of problems organized around the 20 core algorithmic patterns (sliding window, two pointers, cyclic sort, backtracking, and more) that recur across the majority of coding interview questions.
How many problems does it have?
180 problems across 34 sub-sections, grouped under the 20 named patterns.
Is it free to use?
Yes. Browsing every problem on this page is completely free, with no account required. Creating a free DevsUnite account lets you save your checked-off progress, star favorites, and add personal notes that sync across devices.
Do I need an account to track my progress?
You can read and solve every problem without logging in. An account is only required to mark a problem as done, star it, or add a note. Those actions save to your account instead of resetting on refresh.