This content originally appeared on DEV Community and was authored by Alex Hunter
What is Blind 75 — and Why Everyone Talks About It
If you’ve been anywhere near the coding interview grind, you’ve probably seen people mention the “Blind 75.” It’s not a mythical list, nor a secret cheat code. It’s a carefully curated set of 75 LeetCode problems that cover the majority of patterns you’ll face in technical interviews.
The origin goes back to the Blind forum, where frustrated developers kept asking: “Which problems should I focus on to actually pass FAANG interviews?” Eventually, a seasoned engineer compiled the most frequently asked questions into one efficient roadmap — now famous as Blind 75.
Why does it matter? Because out of thousands of LeetCode problems, only a fraction actually appear repeatedly in interviews. Blind 75 filters the noise. Instead of drowning in problem #3251, you can focus on the 20% that yield 80% of results.
The Complete Blind 75 Problem List (Organized by Category)
Blind 75 isn’t just a random collection. It spans across all major patterns that hiring managers expect you to know.
Arrays & Hashing
- Two Sum
- Valid Anagram
- Contains Duplicate
- …
Sliding Window
- Best Time to Buy and Sell Stock
- Longest Substring Without Repeating Characters
- Minimum Window Substring
- …
Dynamic Programming
- Climbing Stairs
- Coin Change
- Longest Increasing Subsequence
- …
Graph & Tree
- Number of Islands
- Clone Graph
- Lowest Common Ancestor of a Binary Tree
- … Check out the full list of problem here
Tip: Don’t just memorize solutions. Tagging problems by pattern will make you a much stronger problem solver.
How to Study Blind 75 (and Actually Retain It)
Blind 75 is powerful, but only if you approach it strategically. Here’s a suggested plan:
- Start simple: Warm up with arrays and strings.
- Move to medium: Sliding window, binary search, backtracking.
- Tackle the hard stuff: Dynamic programming, graphs, system design questions.
- Review & repeat: Spaced repetition is key. Redo old problems after a week, then after a month.
A practical timeline:
- Beginner: 10–12 weeks (1 problem per day, weekends off).
- Intermediate: 6–8 weeks (2–3 problems per day).
- Aggressive: 30 days sprint (not recommended unless desperate).
Common Mistakes People Make with Blind 75
- Grinding without reflection: Solving doesn’t equal learning. Always write down the approach and key insight.
- Skipping hard problems: Dynamic programming and graphs are unavoidable. Don’t procrastinate.
- Not simulating interviews: Solving alone is different from explaining under pressure.
- Treating it as a checklist: Blind 75 is a foundation, not the final destination.
How AI Can Supercharge Your Blind 75 Journey 
Here’s where the 2025 approach differs from the 2018 one. Today, you don’t have to grind alone. AI-assisted tools can help you practice smarter:
- Guided hints, not spoilers: Instead of reading the solution immediately, get step-by-step nudges that train your thinking.
- Auto-generated study notes: Every time you solve, instantly capture a summary: problem statement, key approach, complexity analysis, pitfalls.
- Mock interviews with AI interviewers: Role-play technical interviews with different styles (supportive, aggressive, FAANG-style).
- Visualization of algorithms: Watch your code execute step-by-step, seeing data structures evolve in real time.
This is exactly what LeetCopilot is built for. It doesn’t replace practice, but it makes practice stick.
FAQ — The Questions Everyone Googles
Q: What is Blind 75?
A set of 75 essential LeetCode problems that cover core interview patterns.
Q: Is Blind 75 enough to pass interviews?
It’s a strong foundation. Many people land jobs after mastering Blind 75, but you’ll still need system design and behavioral prep.
Q: How long does it take to finish Blind 75?
Anywhere from 1–3 months depending on pace.
Q: Should I memorize solutions?
No. Focus on recognizing patterns. The same technique (e.g. sliding window) applies to dozens of problems.
Final Thoughts: From Burnout to Breakthrough
Blind 75 became famous because it gave people hope: a clear path through the chaos of coding interviews. But remember, it’s not just about checking off 75 boxes. It’s about learning the language of algorithms.
If you’re serious about mastering these problems without burning out, consider pairing Blind 75 with smarter tools. That’s where LeetCopilot comes in — an AI sidekick that helps you get unstuck, learn patterns faster, and practice interviews in a realistic way.
Try it out: LeetCopilot.dev
This content originally appeared on DEV Community and was authored by Alex Hunter