LeetCode Patterns by Frequency: Top 75, Blind 75, Neetcode 150 Compared

LeetCode has 3,000+ problems. You can’t solve them all, and you don’t need to. The right preparation focuses on the ~75–150 problems that exercise the patterns interviewers actually ask. This guide compares the standard problem lists (Top 75, Blind 75, Neetcode 150), explains the patterns each emphasizes, and provides a calibrated prep roadmap based on what target companies actually ask in 2026.

The Underlying Pattern Set

Coding interview problems aren’t random. Most exercise one of ~20 patterns:

Two pointers (Two Sum sorted, palindrome check, container with most water)
Sliding window (longest substring without repeats, max sum subarray of size k)
Hash map (Two Sum, group anagrams, valid anagram)
Stack (valid parentheses, min stack, evaluate RPN)
Binary search (search rotated array, find peak element)
Linked list manipulation (reverse, detect cycle, merge sorted)
Tree traversal (DFS, BFS, level order, serialize/deserialize)
Tree DP (max depth, balanced check, diameter)
Graph (DFS, BFS, topological sort, Dijkstra)
Union-find (number of islands, connected components)
Heap / priority queue (kth largest, merge k sorted)
Backtracking (subsets, permutations, combinations, n-queens)
Dynamic programming — 1D (climbing stairs, house robber, LIS)
Dynamic programming — 2D (LCS, edit distance, unique paths)
Greedy (interval scheduling, jump game)
Bit manipulation (single number, power of two, hamming weight)
Math / number theory (count primes, happy number)
String manipulation (palindrome, anagrams)
Trie (word search, design dictionary)
Monotonic stack/deque (next greater, sliding window max)

If you’ve internalized these 20 patterns and practiced 5–10 problems within each, you can solve most interview problems even ones you haven’t seen before.

Originated from a Blind post listing the most-impactful 75 problems. Coverage:

Arrays and hashing: 9 problems
Two pointers: 5
Sliding window: 6
Stack: 7
Binary search: 7
Linked list: 6
Trees: 11
Tries: 3
Heap / priority queue: 4
Backtracking: 7
Graphs: 6
Advanced graphs: 6
1D DP: 12
2D DP: 11
Greedy: 8
Intervals: 6
Math: 7
Bit manipulation: 7

The list is compact (75 problems is achievable in 2–3 months), grouped by pattern, and widely recognized.

It’s light on certain patterns (graphs, advanced DP), and some problems fall below the FAANG difficulty bar.

Use it for first-pass prep. Cover all 75 to build pattern recognition. After completing, assess where you’re weak and supplement.

Neetcode 150

Extension of Top 75 with 75 additional problems for deeper coverage. Same pattern structure with more problems per pattern.

It’s more comprehensive than Top 75, reinforces each pattern with 2–3x the problems, and Neetcode’s video explanations are excellent.

150 problems requires 3–5 months at a moderate pace, and it can become its own goal rather than a means.

Use it after Top 75. The additional problems build deeper pattern fluency. Particularly useful for senior+ candidates targeting tougher loops.

Sean Prashad’s LeetCode Patterns List

Smaller list (~150 problems) organized by company. Strengths: company-specific signal (problems Google asks, problems Amazon asks). Weaknesses: less rigorous pattern grouping.

Useful as a supplement when targeting a specific company.

Company-Specific LeetCode Filters

LeetCode Premium ($35/month) has filters by company. Recent (last 6 months / 1 year) questions for each company. The signal:

Most useful when targeting a specific company. Knowing what Amazon asked in the past 6 months lets you focus prep.
Less useful for general prep. The patterns are similar across companies; the specific problems differ.

Worth Premium if you’re focused on 1–2 target companies.

Calibrated Prep Roadmap

Target: FAANG L4–L5 (mid-to-senior)

Top 75 (or Neetcode 150) — 2–3 months at 1 problem/day pace
Company-specific LeetCode filter for your top 1–2 targets — 2 weeks
System design (separate prep) — 1 month. At L4 this is usually one round; at L5 it carries real weight. Interviewers probe how you scope an ambiguous prompt, pick a data store, and reason about a bottleneck out loud, so practice talking through tradeoffs instead of memorizing reference diagrams.
Behavioral / story bank — 2 weeks. Write out six to eight stories covering conflict, failure, leadership, and ambiguity, each in STAR form, then map them to the principles your target company scores on. Interviewers push on your individual contribution, so keep the ‘I’ distinct from the ‘we’.

Total: 3–4 months for serious prep.

Target: FAANG L6+ (staff)

Top 75 / Neetcode 150 (mostly review for senior engineers; build speed) — 6–8 weeks
System design (heaviest weight at this level) — 6–8 weeks
Behavioral / story bank with senior-scope stories — 3 weeks

Total: 4–5 months.

Target: Quant trading firms

LeetCode patterns are real but secondary to probability and brainteasers — 1 month for coding
Probability and brainteasers — 2 months. Focus on conditional probability, expected value, and combinatorics: the questions where you compute an exact answer under time pressure. Interviewers care about the reasoning, so narrate each step and state your assumptions as you go.
Mental math — ongoing. Drill fast arithmetic, fraction-to-decimal conversions, and estimation without a calculator; some firms run timed rounds where speed and accuracy both count. A few minutes of timed drills a day builds the reflex.
Market-making / quant-specific — 1 month. Learn how market makers quote a bid and ask, manage inventory, and think about edge and adverse selection. Many loops include a trading game where you update your prices as the interviewer feeds you new information, so practice pricing exercises where you adjust a number under pressure.

See our Quant Finance Interview Guide for the full quant prep treatment.

Target: AI labs (OpenAI, Anthropic, etc.)

Standard coding (similar to FAANG) — 2 months. Expect the same pattern set, but often a higher bar on writing clean, working code quickly. Some labs swap the abstract puzzle for a practical task (parsing, data manipulation, or a small ML utility), so practice code that actually runs, not whiteboard pseudocode.
ML systems / research round (depends on role) — 1 month. For research-adjacent roles, be ready to explain training pipelines, evaluation, and the tradeoffs behind model or data choices; for infra roles, expect distributed systems and GPU throughput questions. Know your own past projects cold, because interviewers dig into the decisions you made and the alternatives you rejected.
Project deep-dive prep — ongoing. Pick two or three projects you can walk through end to end: the problem, your specific role, what you tried, and what you would change. Interviewers probe for depth, so be ready to defend design choices and put numbers on the impact.

How to Practice (Not Just Solve)

Solving a problem isn’t the same as learning it. Effective practice:

First attempt: 30 minutes solo

Set a timer. Try to solve. Write actual code, not pseudocode. If stuck after 30 minutes, look at hints (not full solution).

Look at solution after solo attempt

Don’t peek too early. The struggle is part of the learning. After 30 minutes, look up the solution and understand it deeply.

Re-solve from scratch the next day

Knowing the solution is not the same as being able to write it. Re-solving from memory consolidates the pattern.

Track patterns, not problems

Maintain a list: “two-pointer problems I’ve done”, “DP problems I’ve done”. Over time, patterns become recognizable; you see a new problem and immediately think “this is the sliding window pattern.”

Spaced repetition

Re-do hard problems 1 week later, 2 weeks later, 1 month later. Pattern recognition decays without repetition.

Common Prep Mistakes

Solving 200 problems randomly. Coverage matters more than count. 75 problems covering 20 patterns >> 200 problems covering 5 patterns.
Spending too much time on hard problems. Most interview questions are medium-difficulty. Focus on medium fluency before hard mastery.
Ignoring system design. By senior level, system design is half the loop. Don’t over-invest in coding at the expense of system design.
Not practicing under time pressure. Solo solving without time pressure doesn’t build interview fluency. Use mock interviews and timed practice.
Memorizing solutions instead of patterns. Pattern fluency transfers to new problems; solution memorization doesn’t. Internalize the underlying pattern.
Avoiding behavioral prep. A passing coding round + bombed behavioral = no offer. Allocate time across all dimensions.

Frequently Asked Questions

How many LeetCode problems do I really need to solve?

For FAANG L4–L5: 75–150 problems with strong pattern fluency. For FAANG L6+: same 75–150 with deeper coverage of harder patterns. For competitive HFT firms: 150+ including some hard / contest-style. Pure problem count matters less than pattern coverage and fluency under time pressure.

Should I do problems in order or by topic?

By topic. Pick a pattern (e.g., sliding window), do 5–8 problems within it, then move to the next pattern. This builds pattern recognition. Random ordering gives breadth at the cost of depth; topic ordering gives depth at the cost of breadth. Topic ordering is better for interview prep specifically.

Is LeetCode Premium worth it?

For company-specific prep, yes. The recent-questions filter for your target company is the real value. For general prep, no — the free problems are sufficient. Premium for the 1–2 month window before your target loops; cancel after.

What’s the right pace for solving problems?

1 problem per day during active prep. Each problem takes 1–2 hours including the re-solve. For 3-month prep, that’s ~90 problems with full understanding. Faster paces (3–4/day) often involve memorizing without internalizing; slower paces don’t build the cadence interview-style problems require.

How does prep change for senior+ candidates?

Less time on basic LeetCode (you’ve internalized most patterns); more on system design, behavioral, and hard / unfamiliar problems. Senior+ prep is more about depth (you can solve at depth and discuss tradeoffs) than breadth. Two-month focused senior prep can match what new grads do over six months.