The NeetCode 250: the complete list by topic

The NeetCode 250 is the NeetCode 150 plus 100 more problems. It contains 250 problems in total: 60 Easy, 155 Medium and 35 Hard. The NeetCode 150 contains 150 problems: 28 Easy, 101 Medium and 21 Hard. The NeetCode 250 by pattern always shows which of them are live on thita.

This guide presents the NeetCode 250 list by topic, explains what the extra 100 add, and shows how to practise the catalogue on thita. It suits developers who have finished, or are close to finishing, the NeetCode 150 and want more structured extension work. It can also suit learners preparing for interviews who have already learnt the main data structures and algorithms patterns and want a longer sequence.

If you are starting from the beginning, the NeetCode 150 is usually the more manageable starting point. Treat the extra 100 as extension work rather than something to rush through: the value comes from understanding the approach, complexity and edge cases, not from moving through titles as quickly as possible.

How should you read the NeetCode 250 list by topic?

The tables below are organised using NeetCode topics. Each table includes four columns:

• Problem: the problem title in the NeetCode 250 catalogue.
• Difficulty: Easy, Medium or Hard.
• In NeetCode 150: whether the problem also appears in the NeetCode 150. Yes identifies a shared problem; No identifies one of the extra 100.
• Our pattern: the DSA pattern used to group the problem on thita. This is thita’s pattern label, so it may differ from the NeetCode topic.

Use the NeetCode topic to plan coverage, then use the pattern column to understand the technique being practised. For example, Arrays & Hashing includes hashing, in-place modification, prefix or suffix calculations and design work. Topic labels help you navigate the catalogue; pattern labels help you organise revision by approach.

The tables include every problem in the catalogue supplied for this article. Links appear only where the corresponding problem is available on thita.

Arrays & Hashing (22 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Concatenation of Array	Easy	No	In-place Rotation
Contains Duplicate	Easy	Yes	Hashing - Previously Seen / Existence Check
Valid Anagram	Easy	Yes	Hashing - Frequency Map / Counting
Two Sum	Easy	Yes	Hashing - Frequency Map / Counting
Longest Common Prefix	Easy	No	Naive / KMP / Rabin-Karp
Group Anagrams	Medium	Yes	Hashing - Frequency Map / Counting
Remove Element	Easy	No	In-place Array Modification
Majority Element	Easy	No	Hashing - Frequency Map / Counting
Design HashSet	Easy	No	Hashing - Previously Seen / Existence Check
Design HashMap	Easy	No	Design (General/Specific)
Sort an Array	Medium	No	Sorting Based
Sort Colors	Medium	No	In-place Array Modification
Top K Frequent Elements	Medium	Yes	Top K Elements (Selection/Frequency)
Encode and Decode Strings	Medium	Yes	Design (General/Specific)
Range Sum Query 2D Immutable	Medium	No	Prefix Sum - Subarray Sum / Range Query
Product of Array Except Self	Medium	Yes	Product Except Self (Prefix/Suffix Products)
Valid Sudoku	Medium	Yes	Hashing - Previously Seen / Existence Check
Longest Consecutive Sequence	Medium	Yes	Hashing - Previously Seen / Existence Check
Best Time to Buy And Sell Stock II	Medium	No	Stock problems
Majority Element II	Medium	No	Hashing - Frequency Map / Counting
Subarray Sum Equals K	Medium	No	Hashing - Frequency Map / Counting
First Missing Positive	Hard	No	Array - Cyclic Sort

Two Pointers (13 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Reverse String	Easy	No	String Reversal
Valid Palindrome	Easy	Yes	Palindrome Check (Two Pointers / Reverse)
Valid Palindrome II	Easy	No	Palindrome Check (Two Pointers / Reverse)
Merge Strings Alternately	Easy	No	In-place Array Modification
Merge Sorted Array	Easy	No	Merge Sorted Array (In-place from End)
Remove Duplicates From Sorted Array	Easy	No	In-place Array Modification
Two Sum II Input Array Is Sorted	Medium	Yes	Converging (Sorted Array Target Sum)
3Sum	Medium	Yes	Converging (Sorted Array Target Sum)
4Sum	Medium	No	Converging (Sorted Array Target Sum)
Rotate Array	Medium	No	In-place Rotation
Container With Most Water	Medium	Yes	Converging (Sorted Array Target Sum)
Boats to Save People	Medium	No	Converging (Sorted Array Target Sum)
Trapping Rain Water	Hard	Yes	In-place Array Modification

Sliding Window (9 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Contains Duplicate II	Easy	No	Variable Size (Condition-Based)
Best Time to Buy And Sell Stock	Easy	Yes	Stock problems
Longest Substring Without Repeating Characters	Medium	Yes	Variable Size (Condition-Based)
Longest Repeating Character Replacement	Medium	Yes	Variable Size (Condition-Based)
Permutation In String	Medium	Yes	Character Frequency Matching
Minimum Size Subarray Sum	Medium	No	Variable Size (Condition-Based)
Find K Closest Elements	Medium	No	Find First/Last Occurrence
Minimum Window Substring	Hard	Yes	Variable Size (Condition-Based)
Sliding Window Maximum	Hard	Yes	Monotonic Queue for Max/Min

Stack (15 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Baseball Game	Easy	No	Simulation / Backtracking Helper
Valid Parentheses	Easy	Yes	Valid Parentheses Matching
Implement Stack Using Queues	Easy	No	Design (General/Specific)
Implement Queue using Stacks	Easy	No	Design (General/Specific)
Min Stack	Medium	Yes	Stack - Min Stack Design
Evaluate Reverse Polish Notation	Medium	Yes	Expression Evaluation (RPN/Infix)
Generate Parentheses	Medium	Yes	Parentheses Generation
Asteroid Collision	Medium	No	Simulation / Backtracking Helper
Daily Temperatures	Medium	Yes	Monotonic Stack
Online Stock Span	Medium	No	Monotonic Stack
Car Fleet	Medium	Yes	Monotonic Stack
Simplify Path	Medium	No	Simulation / Backtracking Helper
Decode String	Medium	No	Simulation / Backtracking Helper
Maximum Frequency Stack	Hard	No	Stack - Min Stack Design
Largest Rectangle In Histogram	Hard	Yes	Largest Rectangle in Histogram

Binary Search (14 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Binary Search	Easy	Yes	On Sorted Array/List
Search Insert Position	Easy	No	On Sorted Array/List
Guess Number Higher Or Lower	Easy	No	On Sorted Array/List
Sqrt(x)	Easy	No	On Sorted Array/List
Search a 2D Matrix	Medium	Yes	On Sorted Array/List
Koko Eating Bananas	Medium	Yes	On Answer / Condition Function
Capacity to Ship Packages Within D Days	Medium	No	On Answer / Condition Function
Find Minimum In Rotated Sorted Array	Medium	Yes	Find Min/Max in Rotated Sorted Array
Search In Rotated Sorted Array	Medium	Yes	Find Min/Max in Rotated Sorted Array
Search In Rotated Sorted Array II	Medium	No	Find Min/Max in Rotated Sorted Array
Time Based Key Value Store	Medium	Yes	Design (General/Specific)
Split Array Largest Sum	Hard	No	On Answer / Condition Function
Median of Two Sorted Arrays	Hard	Yes	Median and Kth of Two Sorted Arrays
Find in Mountain Array	Hard	No	Find Min/Max in Rotated Sorted Array

Linked List (14 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Reverse Linked List	Easy	Yes	In-place Reversal
Merge Two Sorted Lists	Easy	Yes	Merging Two Sorted Lists
Linked List Cycle	Easy	Yes	Fast & Slow (Cycle Detection)
Reorder List	Medium	Yes	Reordering / Partitioning
Remove Nth Node From End of List	Medium	Yes	Fixed Separation (Nth Node from End)
Copy List With Random Pointer	Medium	Yes	Deep Copy / Cloning
Add Two Numbers	Medium	Yes	Addition of Numbers
Find The Duplicate Number	Medium	Yes	Fast & Slow (Cycle Detection)
Reverse Linked List II	Medium	No	In-place Reversal
Design Circular Queue	Medium	No	Design (General/Specific)
LRU Cache	Medium	Yes	Design (General/Specific)
LFU Cache	Hard	No	Design (General/Specific)
Merge K Sorted Lists	Hard	Yes	K-way Merge
Reverse Nodes In K Group	Hard	Yes	In-place Reversal

Trees (23 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Binary Tree Inorder Traversal	Easy	No	Recursive Inorder Traversal
Binary Tree Preorder Traversal	Easy	No	Recursive Preorder Traversal
Binary Tree Postorder Traversal	Easy	No	Recursive Postorder Traversal
Invert Binary Tree	Easy	Yes	Recursive Preorder Traversal
Maximum Depth of Binary Tree	Easy	Yes	Recursive Postorder Traversal
Diameter of Binary Tree	Easy	Yes	Recursive Postorder Traversal
Balanced Binary Tree	Easy	Yes	Recursive Postorder Traversal
Same Tree	Easy	Yes	Recursive Preorder Traversal
Subtree of Another Tree	Easy	Yes	Serialization and Deserialization
Lowest Common Ancestor of a Binary Search Tree	Medium	Yes	Lowest Common Ancestor (LCA) Finding
Insert into a Binary Search Tree	Medium	No	Recursive Preorder Traversal
Delete Node in a BST	Medium	No	Recursive Inorder Traversal
Binary Tree Level Order Traversal	Medium	Yes	Level Order Traversal
Binary Tree Right Side View	Medium	Yes	Level Order Traversal
Construct Quad Tree	Medium	No	Recursive Preorder Traversal
Count Good Nodes In Binary Tree	Medium	Yes	Recursive Preorder Traversal
Validate Binary Search Tree	Medium	Yes	Recursive Inorder Traversal
Kth Smallest Element In a Bst	Medium	Yes	Recursive Inorder Traversal
Construct Binary Tree From Preorder And Inorder Traversal	Medium	Yes	Recursive Preorder Traversal
House Robber III	Medium	No	Recursive Postorder Traversal
Delete Leaves With a Given Value	Medium	No	Recursive Postorder Traversal
Binary Tree Maximum Path Sum	Hard	Yes	Recursive Postorder Traversal
Serialize And Deserialize Binary Tree	Hard	Yes	Serialization and Deserialization

Heap / Priority Queue (12 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Kth Largest Element In a Stream	Easy	Yes	Top K Elements (Selection/Frequency)
Last Stone Weight	Easy	Yes	Top K Elements (Selection/Frequency)
K Closest Points to Origin	Medium	Yes	Top K Elements (Selection/Frequency)
Kth Largest Element In An Array	Medium	Yes	Top K Elements (Selection/Frequency)
Task Scheduler	Medium	Yes	Task Scheduling (Frequency Based)
Design Twitter	Medium	Yes	K-way Merge
Single Threaded CPU	Medium	No	Scheduling / Minimum Cost (Greedy with Priority Queue)
Reorganize String	Medium	No	Scheduling / Minimum Cost (Greedy with Priority Queue)
Longest Happy String	Medium	No	Scheduling / Minimum Cost (Greedy with Priority Queue)
Car Pooling	Medium	No	Line Sweep
Find Median From Data Stream	Hard	Yes	Two Heaps for Median Finding
IPO	Hard	No	Scheduling / Minimum Cost (Greedy with Priority Queue)

Backtracking (16 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Sum of All Subsets XOR Total	Easy	No	Subsets (Include/Exclude)
Subsets	Medium	Yes	Subsets (Include/Exclude)
Combination Sum	Medium	Yes	Combination Sum
Combination Sum II	Medium	Yes	Combination Sum
Combinations	Medium	No	Subsets (Include/Exclude)
Permutations	Medium	Yes	Permutations
Subsets II	Medium	Yes	Subsets (Include/Exclude)
Permutations II	Medium	No	Permutations
Word Search	Medium	Yes	Word Search / Path Finding in Grid
Palindrome Partitioning	Medium	Yes	Palindrome Partitioning
Letter Combinations of a Phone Number	Medium	Yes	Subsets (Include/Exclude)
Matchsticks to Square	Medium	No	N-Queens / Constraint Satisfaction
Partition to K Equal Sum Subsets	Medium	No	Combination Sum
N Queens	Hard	Yes	N-Queens / Constraint Satisfaction
N Queens II	Hard	No	N-Queens / Constraint Satisfaction
Word Break II	Hard	No	1D Array (Word Break Style)

Tries (4 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Implement Trie Prefix Tree	Medium	Yes	Tries
Design Add And Search Words Data Structure	Medium	Yes	Tries
Extra Characters in a String	Medium	No	Tries
Word Search II	Hard	Yes	Word Search / Path Finding in Grid

Graphs (21 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Island Perimeter	Easy	No	Graph DFS - Connected Components / Island Counting
Verifying An Alien Dictionary	Easy	No	Hashing - Frequency Map / Counting
Find the Town Judge	Easy	No	Hashing - Frequency Map / Counting
Number of Islands	Medium	Yes	Graph DFS - Connected Components / Island Counting
Max Area of Island	Medium	Yes	Graph DFS - Connected Components / Island Counting
Clone Graph	Medium	Yes	Deep Copy / Cloning
Walls And Gates	Medium	Yes	Graph BFS - Connected Components / Island Counting
Rotting Oranges	Medium	Yes	Graph BFS - Connected Components / Island Counting
Pacific Atlantic Water Flow	Medium	Yes	Graph DFS - Connected Components / Island Counting
Surrounded Regions	Medium	Yes	Graph DFS - Connected Components / Island Counting
Open The Lock	Medium	No	Bidirectional BFS (BFS optimization for known source & target)
Course Schedule	Medium	Yes	Graph DFS - Cycle Detection (Directed Graph)
Course Schedule II	Medium	Yes	Graph DFS - Cycle Detection (Directed Graph)
Graph Valid Tree	Medium	Yes	Union-Find (Disjoint Set Union - DSU)
Course Schedule IV	Medium	No	Graph BFS - Topological Sort (Kahn's Algorithm)
Number of Connected Components In An Undirected Graph	Medium	Yes	Union-Find (Disjoint Set Union - DSU)
Redundant Connection	Medium	Yes	Union-Find (Disjoint Set Union - DSU)
Accounts Merge	Medium	No	Union-Find (Disjoint Set Union - DSU)
Evaluate Division	Medium	No	Graph DFS - Connected Components / Island Counting
Minimum Height Trees	Medium	No	Graph BFS - Topological Sort (Kahn's Algorithm)
Word Ladder	Hard	Yes	Graph BFS - Connected Components / Island Counting

Advanced Graphs (10 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Path with Minimum Effort	Medium	No	Shortest Path (Dijkstra's Algorithm)
Network Delay Time	Medium	Yes	Shortest Path (Dijkstra's Algorithm)
Reconstruct Itinerary	Hard	Yes	Simulation / Backtracking Helper
Min Cost to Connect All Points	Medium	Yes	Minimum Spanning Tree (Kruskal / Prim / DSU + heap)
Swim In Rising Water	Hard	Yes	Shortest Path (Dijkstra's Algorithm)
Alien Dictionary	Hard	Yes	Graph BFS - Topological Sort (Kahn's Algorithm)
Cheapest Flights Within K Stops	Medium	Yes	Shortest Path (Bellman-Ford / BFS+K)
Find Critical and Pseudo Critical Edges in Minimum Spanning Tree	Hard	No	Bridges & Articulation Points (Tarjan low-link)
Build a Matrix With Conditions	Hard	No	Graph BFS - Topological Sort (Kahn's Algorithm)
Greatest Common Divisor Traversal	Hard	No	Union-Find (Disjoint Set Union - DSU)

1-D Dynamic Programming (17 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Climbing Stairs	Easy	Yes	1D Array (Fibonacci Style)
Min Cost Climbing Stairs	Easy	Yes	1D Array (Fibonacci Style)
N-th Tribonacci Number	Easy	No	1D Array (Fibonacci Style)
House Robber	Medium	Yes	1D Array (Fibonacci Style)
House Robber II	Medium	Yes	1D Array (Fibonacci Style)
Longest Palindromic Substring	Medium	Yes	Expanding From Center (Palindromes)
Palindromic Substrings	Medium	Yes	Expanding From Center (Palindromes)
Decode Ways	Medium	Yes	1D Array (Fibonacci Style)
Coin Change	Medium	Yes	1D Array (Coin Change / Unbounded Knapsack Style)
Maximum Product Subarray	Medium	Yes	1D Array (Kadane's Algorithm for Max/Min Subarray)
Word Break	Medium	Yes	1D Array (Word Break Style)
Longest Increasing Subsequence	Medium	Yes	Longest Increasing Subsequence (LIS)
Partition Equal Subset Sum	Medium	Yes	1D Array (0/1 Knapsack Subset Sum Style)
Combination Sum IV	Medium	No	1D Array (Coin Change / Unbounded Knapsack Style)
Perfect Squares	Medium	No	1D Array (Coin Change / Unbounded Knapsack Style)
Integer Break	Medium	No	1D Array (Fibonacci Style)
Stone Game III	Hard	No	1D Array (Fibonacci Style)

2-D Dynamic Programming (16 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Unique Paths	Medium	Yes	2D Array (Unique Paths on Grid)
Unique Paths II	Medium	No	2D Array (Unique Paths on Grid)
Minimum Path Sum	Medium	No	2D Array (Unique Paths on Grid)
Longest Common Subsequence	Medium	Yes	2D Array (Longest Common Subsequence - LCS)
Last Stone Weight II	Medium	No	1D Array (0/1 Knapsack Subset Sum Style)
Best Time to Buy And Sell Stock With Cooldown	Medium	Yes	Stock problems
Coin Change II	Medium	Yes	1D Array (Coin Change / Unbounded Knapsack Style)
Target Sum	Medium	Yes	1D Array (0/1 Knapsack Subset Sum Style)
Interleaving String	Medium	Yes	2D Array (Unique Paths on Grid)
Stone Game	Medium	No	Interval DP
Stone Game II	Medium	No	Interval DP
Longest Increasing Path In a Matrix	Hard	Yes	2D Array (Unique Paths on Grid)
Distinct Subsequences	Hard	Yes	2D Array (Longest Common Subsequence - LCS)
Edit Distance	Medium	Yes	2D Array (Edit Distance / Levenshtein Distance)
Burst Balloons	Hard	Yes	Interval DP
Regular Expression Matching	Hard	Yes	2D Array (Edit Distance / Levenshtein Distance)

Greedy (14 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Lemonade Change	Easy	No	Sorting Based
Maximum Subarray	Medium	Yes	1D Array (Kadane's Algorithm for Max/Min Subarray)
Maximum Sum Circular Subarray	Medium	No	1D Array (Kadane's Algorithm for Max/Min Subarray)
Longest Turbulent Subarray	Medium	No	Variable Size (Condition-Based)
Jump Game	Medium	Yes	Jump Game Reachability/Minimization
Jump Game II	Medium	Yes	Jump Game Reachability/Minimization
Jump Game VII	Medium	No	Variable Size (Condition-Based)
Gas Station	Medium	Yes	Gas Station Circuit
Hand of Straights	Medium	Yes	Sorting Based
Dota2 Senate	Medium	No	Task Scheduling (Frequency Based)
Merge Triplets to Form Target Triplet	Medium	Yes	Sorting Based
Partition Labels	Medium	Yes	Line Sweep
Valid Parenthesis String	Medium	Yes	Valid Parentheses Matching
Candy	Hard	No	Sorting Based

Intervals (7 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Insert Interval	Medium	Yes	Interval Merging/Scheduling
Merge Intervals	Medium	Yes	Interval Merging/Scheduling
Non Overlapping Intervals	Medium	Yes	Interval Merging/Scheduling
Meeting Rooms	Easy	Yes	Interval Merging/Scheduling
Meeting Rooms II	Medium	Yes	Scheduling / Minimum Cost (Greedy with Priority Queue)
Meeting Rooms III	Hard	No	Scheduling / Minimum Cost (Greedy with Priority Queue)
Minimum Interval to Include Each Query	Hard	Yes	Scheduling / Minimum Cost (Greedy with Priority Queue)

Math & Geometry (13 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Excel Sheet Column Title	Easy	No	Integer and Roman Conversion
Greatest Common Divisor of Strings	Easy	No	Repeated Substring Pattern Detection
Insert Greatest Common Divisors in Linked List	Medium	No	Reordering / Partitioning
Transpose Matrix	Easy	No	In-place Rotation
Rotate Image	Medium	Yes	In-place Rotation
Spiral Matrix	Medium	Yes	Spiral Traversal
Set Matrix Zeroes	Medium	Yes	Set Matrix Zeroes (In-place Marking)
Happy Number	Easy	Yes	Fast & Slow (Cycle Detection)
Plus One	Easy	Yes	Plus One (Handling Carry)
Roman to Integer	Easy	No	Integer and Roman Conversion
Pow(x, n)	Medium	Yes	Bitwise Operations - Power of Two/Four Check
Multiply Strings	Medium	Yes	Plus One (Handling Carry)
Detect Squares	Medium	Yes	Design (General/Specific)

Bit Manipulation (10 problems)

Problem	Difficulty	In NeetCode 150	Pattern on thita
Single Number	Easy	Yes	Bitwise XOR - Finding Single/Missing Number
Number of 1 Bits	Easy	Yes	Bitwise AND - Counting Set Bits (Hamming Weight)
Counting Bits	Easy	Yes	Bitwise DP - Counting Bits Optimization
Add Binary	Easy	No	Plus One (Handling Carry)
Reverse Bits	Easy	Yes	Bitwise AND - Counting Set Bits (Hamming Weight)
Missing Number	Easy	Yes	Bitwise XOR - Finding Single/Missing Number
Sum of Two Integers	Medium	Yes	Bitwise XOR - Finding Single/Missing Number
Reverse Integer	Medium	Yes	String Reversal
Bitwise AND of Numbers Range	Medium	No	Bitwise Operations - Power of Two/Four Check
Minimum Array End	Medium	No	Bitwise Operations - Power of Two/Four Check

What does the NeetCode 250 list by topic add to the NeetCode 150?

The extra 100 broaden the catalogue across every NeetCode topic. They are not distributed evenly, so the expansion changes the emphasis of each topic. The figures below show how many additional problems each topic contributes beyond the NeetCode 150.

• Arrays & Hashing adds 13 problems, increasing the topic from 9 to 22.
• Two Pointers adds 8, increasing it from 5 to 13.
• Sliding Window adds 3, increasing it from 6 to 9.
• Stack adds 8, increasing it from 7 to 15.
• Binary Search adds 7, increasing it from 7 to 14.
• Linked List adds 3, increasing it from 11 to 14.
• Trees adds 8, increasing it from 15 to 23.
• Heap / Priority Queue adds 5, increasing it from 7 to 12.
• Backtracking adds 7, increasing it from 9 to 16.
• Tries adds 1, increasing it from 3 to 4.
• Graphs adds 8, increasing it from 13 to 21.
• Advanced Graphs adds 4, increasing it from 6 to 10.
• 1-D Dynamic Programming adds 5, increasing it from 12 to 17.
• 2-D Dynamic Programming adds 5, increasing it from 11 to 16.
• Greedy adds 6, increasing it from 8 to 14.
• Intervals adds 1, increasing it from 6 to 7.
• Math & Geometry adds 5, increasing it from 8 to 13.
• Bit Manipulation adds 3, increasing it from 7 to 10.

The largest topic by NeetCode 250 total is Trees, with 23 problems, followed by Arrays & Hashing with 22 and Graphs with 21. That does not make these topics automatically more important than the others. It means they contain more material to schedule if you intend to complete the full list.

The expanded list also changes the difficulty mix. The extra 100 contain 32 Easy, 54 Medium and 14 Hard problems. Use those additions to reinforce fundamentals and then work towards more demanding variations. Judge readiness by whether you can explain the approach, analyse complexity and implement it reliably—not simply by how many titles you have seen.

Is the NeetCode 250 worth doing after the NeetCode 150?

The answer depends on your preparation stage. If you have not yet built a foundation in arrays, hash maps, linked lists, trees, graphs and dynamic programming, completing another list may add volume without improving pattern recognition. In that situation, work through a smaller set carefully and learn to identify the relevant pattern.

If you have completed the NeetCode 150 list, practised on thita, and can solve familiar problems without relying on memorised code, use the NeetCode 250 as extension work. The additional problems let you revisit techniques in different forms and expose areas that need more revision.

The NeetCode 250 is also useful when your preparation needs more breadth. Its topics cover foundational structures, advanced graph topics, dynamic programming and design tasks. It is not a guarantee of interview performance, so use it alongside communication practice, complexity analysis and timed problem-solving.

For a comparison with other preparation routes, see the NeetCode 150 vs NeetCode 250 vs Blind 75 comparison. The Blind 75 contains 75 problems, and every one is in the NeetCode 150, so it is a narrower subset rather than an additional source of NeetCode 250 coverage.

What order should you use for the NeetCode 250 problems?

A sensible order is to move from reusable operations to structures and then to more complex state or graph problems. You do not need to follow the table order exactly, but the sequence below limits the number of concepts you must learn at once.

Start with array and string techniques

Begin with Arrays & Hashing, then Two Pointers and Sliding Window. Use these topics to practise frequency counting, lookup, sorting-aware scans, in-place updates and variable-size windows. They also provide techniques that reappear in later topics.

Next study Stack, Binary Search and Intervals. Use Stack problems for matching, simulation and monotonic structures. Binary Search should include both direct searches and searches over an answer condition. Intervals provide practice with sorting, scheduling and overlap reasoning.

Build structure fluency

Move to Linked List, Trees, Heap / Priority Queue and Tries. Focus on pointer movement, recursive and level-order traversal, ordering guarantees, top-k selection and prefix structures. At this stage, use the Our pattern column to separate similar-looking questions that require different invariants.

Add systematic search and optimisation

Study Backtracking and Graphs after you are comfortable with recursion and state tracking. Then cover Advanced Graphs, including shortest paths, minimum spanning trees and topological ordering. These areas reward deliberate tracing: write down the state, the visited condition and the reason an item can be safely removed from consideration.

Follow with 1-D Dynamic Programming and 2-D Dynamic Programming. Start by defining the state and transition in plain language. Only then choose a top-down or bottom-up implementation. Greedy problems can be studied alongside dynamic programming, but compare the proof of a greedy choice with the recurrence of a DP solution rather than assuming that a fast-looking choice is valid.

Finish with Math & Geometry and Bit Manipulation, or interleave them as shorter revision blocks. These topics reward precise handling of representations, boundaries and invariants. Return to difficult problems after a gap instead of immediately reading an editorial.

How can you practise the NeetCode 250 on thita?

The NeetCode 250 by pattern on thita lists the catalogue and connects each problem with thita’s pattern-based organisation. You can also open the DSA patterns sheet filtered to the NeetCode 250. Thita groups DSA problems into 99 DSA patterns in 16 families. The filtered view is useful when you want to practise a technique across topics instead of completing a NeetCode topic from top to bottom.

Every problem on the list that is live on thita runs in the browser in Python, Java, C++, JavaScript, Go and C# against the problem’s test cases. That gives you a practical feedback loop: form a plan, implement it, run the tests, inspect failures and revise the invariant. Use the language you expect to use in interviews, then occasionally practise explaining the same idea in another language if your role requires it.

A productive session has several stages. First, read the prompt and restate the input, output and constraints. Next, identify a likely pattern before writing code. Then implement a straightforward version, test edge cases and record the complexity. Finally, revisit the problem without looking at your previous code and explain why the approach works.

Every problem on the NeetCode 250 is on thita, so every row above links to its problem page.

When you are ready to practise communication as well as implementation, use thita’s AI mock interview. It supports spoken practice, runs your code and asks follow-up questions. That is different from solving silently: you must state assumptions, justify choices, discuss complexity and respond when the interviewer changes a requirement.

A complete preparation loop combines the list, the pattern view and interview-style rehearsal. The NeetCode 250 gives you a structured catalogue; thita gives you browser-based execution and pattern-based revision. Use both deliberately, measure progress by the quality of your reasoning, and revisit weak patterns rather than chasing completion alone.

Thita is not affiliated with NeetCode.