Blind 75 Interview Questions

February 26, 2026 • By Surya Singh • DSA • Blind 75 • LeetCode • Interview

Blind 75 LeetCode problems — the most asked interview questions at FAANG companies.

DSABlind 75LeetCodeInterview

Key Takeaways

  • 1Blind 75 is a curated list of ~75 LeetCode problems that cover most interview patterns.
  • 2Master the patterns: Two Pointers, Sliding Window, DFS/BFS, DP, Backtracking, Heaps, Binary Search.
  • 3Do not memorize solutions—understand why each approach works so you can adapt to variations.
  • 4Practice in order: Arrays & Hashing → Two Pointers → Sliding Window → Stack → Binary Search → Linked List → Trees → Tries → Heap → Backtracking → Graphs → DP.

The questions below are commonly asked in technical interviews. Each answer is written to help you understand the concept clearly and explain it confidently. Focus on understanding the "why" behind each answer—that is what interviewers care about.

In this guide

Interview Questions & Answers

What is the Blind 75 and why is it recommended for interviews?

The Blind 75 is a list of approximately 75 LeetCode problems compiled to cover the most common coding interview patterns. Companies like Google, Amazon, and Meta frequently ask variations of these problems. The list is ordered to build foundational skills: you start with arrays and hashing, then two pointers and sliding window, then move to trees, graphs, and dynamic programming. Completing it gives you exposure to nearly every pattern you will see in real interviews. It is more focused than grinding hundreds of random problems.

How should I approach a Blind 75 problem I have not seen before?

Read the problem carefully and identify the pattern. Ask yourself: Is it about finding pairs? (Two pointers or hash map.) Subarrays? (Sliding window or prefix sums.) Sequences? (DP or backtracking.) Trees? (DFS/BFS, recursion.) Start with a brute-force idea, then optimize. For example, "Two Sum" brute force is O(n²) pairs; optimizing with a hash map gives O(n). Write test cases, including edge cases (empty input, single element). Code cleanly, then analyze time and space complexity.

// Two Sum - hash map O(n)
int[] TwoSum(int[] nums, int target) {
    var seen = new Dictionary<int, int>();
    for (int i = 0; i < nums.Length; i++) {
        int need = target - nums[i];
        if (seen.TryGetValue(need, out int j))
            return new[] { j, i };
        seen[nums[i]] = i;
    }
    return Array.Empty<int>();
}

What are the most important patterns in the Blind 75?

Two Pointers (especially on sorted arrays), Sliding Window (subarray/substring problems), DFS/BFS (trees, graphs), Dynamic Programming (1D and 2D), and Backtracking (combinations/permutations). Hash maps appear in many problems for O(1) lookups. Binary search applies when you can discard half the search space. Heaps (priority queues) for k-largest or merge k sorted lists. Master these patterns; most interview questions are variations that combine them.

How many times should I redo Blind 75 problems?

Aim to solve each problem at least twice without looking at the solution. The first time builds understanding; the second (days or weeks later) tests recall. If you cannot recall the approach, you have not internalized it. Some candidates do the list 2–3 times before interviews. Quality over quantity: it is better to deeply understand 50 problems than to rush through 75 superficially. Also practice explaining your approach out loud—interviews require clear communication.

What if an interview question is not in the Blind 75?

That is expected—interviewers often use variations or new problems. The value of Blind 75 is pattern recognition. A new problem might combine "sliding window" with "hash map" or "BFS" with "state compression." If you know the patterns, you can break the problem down. Practice identifying the pattern within the first minute or two. Ask clarifying questions. Start with a simpler version (e.g., array before matrix), then generalize. The patterns from Blind 75 are the building blocks.

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Surya Singh

Surya Singh

Azure Solutions Architect & AI Engineer

Microsoft-certified Azure Solutions Architect with 8+ years in enterprise software, cloud architecture, and AI/ML deployment. I build production AI systems and write about what actually works—based on shipping code, not theory.

  • Microsoft Certified: Azure Solutions Architect Expert
  • Built 20+ production AI/ML pipelines on Azure
  • 8+ years in .NET, C#, and cloud-native architecture
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