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NeetCode 250Official

NeetCode 150 plus 100 more beginner-friendly problems. The most approachable list for people completely new to algorithms. Each topic has extra easy problems.

By FleetCode249 problems60 Easy154 Medium35 Hard25 followersUpdated 23 Mar 2026

Start: Concatenation of Array

249problems

60Easy

154Medium

35Hard

Signed in, the sheet shows which of these you have solved.

Showing 154 of 249 problems · Medium · Clear

TitleSolutionAcceptDifficultyTopics

49. Group AnagramsVideo

Solution73.0%Medium

Array, Hash Table +2· 87 companies

912. Sort an ArrayVideo

Solution55.9%Medium

Array, Bucket Sort +6· 12 companies

75. Sort ColorsVideo

Solution69.9%Medium

Array, Sorting +1· 37 companies

347. Top K Frequent ElementsVideo

Solution67.3%Medium

Array, Bucket Sort +6· 53 companies

271. Encode and Decode StringsVideoPremium

Solution51.9%Medium

Array, Design +1· 11 companies

304. Range Sum Query 2D - ImmutableVideo

Solution59.2%Medium

Array, Design +2· 10 companies

238. Product of Array Except SelfVideo

Solution69.3%Medium

Array, Prefix Sum· 40 companies

36. Valid SudokuVideo

Solution64.9%Medium

Array, Hash Table +1· 26 companies

128. Longest Consecutive SequenceVideo

Solution47.0%Medium

Array, Hash Table +1· 40 companies

122. Best Time to Buy and Sell Stock IIVideo

Solution71.4%Medium

Array, Dynamic Programming +1· 28 companies

229. Majority Element IIVideo

Solution56.5%Medium

Array, Counting +2· 9 companies

560. Subarray Sum Equals KVideo

Solution48.2%Medium

Array, Hash Table +1· 47 companies

167. Two Sum II - Input Array Is SortedVideo

Solution66.1%Medium

Array, Binary Search +1· 16 companies

15. 3SumVideo

Solution40.1%Medium

Array, Sorting +1· 57 companies

18. 4SumVideo

Solution42.0%Medium

Array, Sorting +1· 20 companies

189. Rotate ArrayVideo

Solution45.3%Medium

Array, Math +1· 27 companies

11. Container With Most WaterVideo

Solution60.9%Medium

Array, Greedy +1· 57 companies

881. Boats to Save PeopleVideo

Solution62.7%Medium

Array, Greedy +2· 11 companies

3. Longest Substring Without Repeating CharactersVideo

Solution39.9%Medium

Hash Table, Sliding Window +1· 104 companies

424. Longest Repeating Character ReplacementVideo

Solution60.4%Medium

Hash Table, Sliding Window +1· 22 companies

567. Permutation in StringVideo

Solution49.8%Medium

Hash Table, Sliding Window +2· 16 companies

209. Minimum Size Subarray SumVideo

Solution53.1%Medium

Array, Binary Search +2· 18 companies

658. Find K Closest ElementsVideo

Solution50.1%Medium

Array, Binary Search +4· 18 companies

155. Min StackVideo

Solution58.5%Medium

Design, Stack· 37 companies

150. Evaluate Reverse Polish NotationVideo

Solution58.5%Medium

Array, Math +1· 18 companies

735. Asteroid CollisionVideo

Solution49.2%Medium

Array, Simulation +1· 32 companies

739. Daily TemperaturesVideo

Solution69.1%Medium

Array, Monotonic Stack +1· 32 companies

901. Online Stock SpanVideo

Solution69.5%Medium

Data Stream, Design +2· 7 companies

853. Car FleetVideo

Solution55.5%Medium

Array, Monotonic Stack +2· 11 companies

71. Simplify PathVideo

Solution51.4%Medium

Stack, String· 24 companies

394. Decode StringVideo

Solution63.0%Medium

Recursion, Stack +1· 40 companies

74. Search a 2D MatrixVideo

Solution54.4%Medium

Array, Binary Search +1· 19 companies

875. Koko Eating BananasVideo

Solution50.4%Medium

Array, Binary Search· 47 companies

1011. Capacity To Ship Packages Within D DaysVideo

Solution74.8%Medium

Array, Binary Search· 20 companies

153. Find Minimum in Rotated Sorted ArrayVideo

Solution55.3%Medium

Array, Binary Search· 18 companies

33. Search in Rotated Sorted ArrayVideo

Solution45.5%Medium

Array, Binary Search· 53 companies

81. Search in Rotated Sorted Array IIVideo

Solution40.4%Medium

Array, Binary Search· 10 companies

981. Time Based Key-Value StoreVideo

Solution49.8%Medium

Binary Search, Design +2· 34 companies

143. Reorder ListVideo

Solution66.6%Medium

Linked List, Recursion +2· 15 companies

19. Remove Nth Node From End of ListVideo

Solution52.4%Medium

Linked List, Two Pointers· 18 companies

138. Copy List with Random PointerVideo

Solution63.8%Medium

Hash Table, Linked List· 22 companies

2. Add Two NumbersVideo

Solution49.3%Medium

Linked List, Math +1· 37 companies

287. Find the Duplicate NumberVideo

Solution64.7%Medium

Array, Binary Search +2· 22 companies

92. Reverse Linked List IIVideo

Solution52.4%Medium

Linked List· 16 companies

622. Design Circular QueueVideo

Solution55.4%Medium

Array, Design +2· 21 companies

146. LRU CacheVideo

Solution48.2%Medium

Design, Doubly-Linked List +2· 120 companies

235. Lowest Common Ancestor of a Binary Search TreeVideo

Solution71.4%Medium

Binary Search Tree, Binary Tree +2· 10 companies

701. Insert into a Binary Search TreeVideo

Solution73.6%Medium

Binary Search Tree, Binary Tree +1· 7 companies

450. Delete Node in a BSTVideo

Solution55.1%Medium

Binary Search Tree, Binary Tree +1· 11 companies

102. Binary Tree Level Order TraversalVideo

Solution73.5%Medium

Binary Tree, Breadth-First Search +1· 16 companies

199. Binary Tree Right Side ViewVideo

Solution71.5%Medium

Binary Tree, Breadth-First Search +2· 14 companies

427. Construct Quad TreeVideo

Solution78.8%Medium

Array, Divide and Conquer +2· 8 companies

1448. Count Good Nodes in Binary TreeVideo

Solution73.8%Medium

Binary Tree, Breadth-First Search +2· 7 companies

98. Validate Binary Search TreeVideo

Solution36.1%Medium

Binary Search Tree, Binary Tree +2· 18 companies

230. Kth Smallest Element in a BSTVideo

Solution77.2%Medium

Binary Search Tree, Binary Tree +2· 12 companies

105. Construct Binary Tree from Preorder and Inorder TraversalVideo

Solution69.7%Medium

Array, Binary Tree +3· 9 companies

337. House Robber IIIVideo

Solution56.3%Medium

Binary Tree, Depth-First Search +2· 13 companies

1325. Delete Leaves With a Given ValueVideo

Solution77.4%Medium

Binary Tree, Depth-First Search +1· 4 companies

973. K Closest Points to OriginVideo

Solution69.4%Medium

Array, Divide and Conquer +5· 17 companies

215. Kth Largest Element in an ArrayVideo

Solution69.4%Medium

Array, Divide and Conquer +3· 41 companies

621. Task SchedulerVideo

Solution64.0%Medium

Array, Counting +4· 24 companies

355. Design TwitterVideo

Solution45.6%Medium

Design, Hash Table +2· 14 companies

1834. Single-Threaded CPUVideo

Solution48.1%Medium

Array, Heap (Priority Queue) +1· 7 companies

767. Reorganize StringVideo

Solution57.5%Medium

Counting, Greedy +4· 20 companies

1405. Longest Happy StringVideo

Solution65.5%Medium

Greedy, Heap (Priority Queue) +1· 8 companies

1094. Car PoolingVideo

Solution56.5%Medium

Array, Heap (Priority Queue) +3· 12 companies

78. SubsetsVideo

Solution82.7%Medium

Array, Backtracking +1· 21 companies

39. Combination SumVideo

Solution76.9%Medium

Array, Backtracking· 26 companies

40. Combination Sum IIVideo

Solution60.3%Medium

Array, Backtracking· 15 companies

77. CombinationsVideo

Solution74.9%Medium

Backtracking· 8 companies

46. PermutationsVideo

Solution82.3%Medium

Array, Backtracking· 25 companies

90. Subsets IIVideo

Solution61.7%Medium

Array, Backtracking +1· 9 companies

47. Permutations IIVideo

Solution64.3%Medium

Array, Backtracking· 9 companies

22. Generate ParenthesesVideo

Solution79.6%Medium

Backtracking, Dynamic Programming +1· 40 companies

79. Word SearchVideo

Solution48.2%Medium

Array, Backtracking +2· 36 companies

131. Palindrome PartitioningVideo

Solution74.4%Medium

Backtracking, Dynamic Programming +1· 10 companies

17. Letter Combinations of a Phone NumberVideo

Solution66.9%Medium

Backtracking, Hash Table +1· 34 companies

473. Matchsticks to SquareVideo

Solution42.3%Medium

Array, Backtracking +3· 9 companies

698. Partition to K Equal Sum SubsetsVideo

Solution38.6%Medium

Array, Backtracking +4· 8 companies

208. Implement Trie (Prefix Tree)Video

Solution69.9%Medium

Design, Hash Table +2· 21 companies

211. Design Add and Search Words Data StructureVideo

Solution48.9%Medium

Depth-First Search, Design +2· 13 companies

2707. Extra Characters in a StringVideo

Solution57.4%Medium

Array, Dynamic Programming +3· 3 companies

200. Number of IslandsVideo

Solution65.2%Medium

Array, Breadth-First Search +3· 86 companies

695. Max Area of IslandVideo

Solution73.9%Medium

Array, Breadth-First Search +3· 20 companies

133. Clone GraphVideo

Solution66.1%Medium

Breadth-First Search, Depth-First Search +2· 18 companies

286. Walls and GatesVideoPremium

Solution63.9%Medium

Array, Breadth-First Search +1· 11 companies

994. Rotting OrangesVideo

Solution59.5%Medium

Array, Breadth-First Search +1· 52 companies

417. Pacific Atlantic Water FlowVideo

Solution61.3%Medium

Array, Breadth-First Search +2· 11 companies

130. Surrounded RegionsVideo

Solution46.1%Medium

Array, Breadth-First Search +3· 12 companies

752. Open the LockVideo

Solution61.2%Medium

Array, Breadth-First Search +2· 15 companies

207. Course ScheduleVideo

Solution52.2%Medium

Breadth-First Search, Depth-First Search +2· 45 companies

210. Course Schedule IIVideo

Solution56.3%Medium

Breadth-First Search, Depth-First Search +2· 36 companies

261. Graph Valid TreeVideoPremium

Solution49.9%Medium

Breadth-First Search, Depth-First Search +2· 9 companies

1462. Course Schedule IVVideo

Solution60.4%Medium

Breadth-First Search, Depth-First Search +2· 6 companies

323. Number of Connected Components in an Undirected GraphVideoPremium

Solution64.9%Medium

Breadth-First Search, Depth-First Search +2· 7 companies

684. Redundant ConnectionVideo

Solution68.0%Medium

Breadth-First Search, Depth-First Search +2· 8 companies

721. Accounts MergeVideo

Solution62.2%Medium

Array, Breadth-First Search +5· 17 companies

399. Evaluate DivisionVideo

Solution64.7%Medium

Array, Breadth-First Search +5· 23 companies

310. Minimum Height TreesVideo

Solution42.4%Medium

Breadth-First Search, Depth-First Search +2· 7 companies

1631. Path With Minimum EffortVideo

Solution64.1%Medium

Array, Binary Search +5· 9 companies

743. Network Delay TimeVideo

Solution61.7%Medium

Breadth-First Search, Depth-First Search +3· 9 companies

1584. Min Cost to Connect All PointsVideo

Solution71.7%Medium

Array, Graph +2· 10 companies

787. Cheapest Flights Within K StopsVideo

Solution42.7%Medium

Breadth-First Search, Depth-First Search +4· 18 companies

198. House RobberVideo

Solution53.6%Medium

Array, Dynamic Programming· 40 companies

213. House Robber IIVideo

Solution45.3%Medium

Array, Dynamic Programming· 19 companies

5. Longest Palindromic SubstringVideo

Solution38.7%Medium

Dynamic Programming, String +1· 81 companies

647. Palindromic SubstringsVideo

Solution73.2%Medium

Dynamic Programming, String +1· 25 companies

91. Decode WaysVideo

Solution38.3%Medium

Dynamic Programming, String· 22 companies

322. Coin ChangeVideo

Solution49.3%Medium

Array, Breadth-First Search +1· 40 companies

152. Maximum Product SubarrayVideo

Solution37.3%Medium

Array, Dynamic Programming· 23 companies

139. Word BreakVideo

Solution49.8%Medium

Array, Dynamic Programming +4· 32 companies

300. Longest Increasing SubsequenceVideo

Solution59.8%Medium

Array, Binary Search +1· 30 companies

416. Partition Equal Subset SumVideo

Solution49.9%Medium

Array, Dynamic Programming· 16 companies

377. Combination Sum IVVideo

Solution55.0%Medium

Array, Dynamic Programming· 7 companies

279. Perfect SquaresVideo

Solution57.0%Medium

Breadth-First Search, Dynamic Programming +1· 12 companies

343. Integer BreakVideo

Solution62.6%Medium

Dynamic Programming, Math· 6 companies

62. Unique PathsVideo

Solution67.3%Medium

Combinatorics, Dynamic Programming +1· 21 companies

63. Unique Paths IIVideo

Solution44.9%Medium

Array, Dynamic Programming +1· 9 companies

64. Minimum Path SumVideo

Solution68.6%Medium

Array, Dynamic Programming +1· 17 companies

1143. Longest Common SubsequenceVideo

Solution59.6%Medium

Dynamic Programming, String· 19 companies

1049. Last Stone Weight IIVideo

Solution61.2%Medium

Array, Dynamic Programming· 5 companies

309. Best Time to Buy and Sell Stock with CooldownVideo

Solution62.4%Medium

Array, Dynamic Programming· 8 companies

518. Coin Change IIVideo

Solution59.1%Medium

Array, Dynamic Programming· 11 companies

494. Target SumVideo

Solution52.6%Medium

Array, Backtracking +1· 10 companies

97. Interleaving StringVideo

Solution45.0%Medium

Dynamic Programming, String· 10 companies

877. Stone GameVideo

Solution77.0%Medium

Array, Dynamic Programming +2· 4 companies

1140. Stone Game IIVideo

Solution75.8%Medium

Array, Dynamic Programming +3· 5 companies

72. Edit DistanceVideo

Solution61.5%Medium

Dynamic Programming, String· 24 companies

53. Maximum SubarrayVideo

Solution53.7%Medium

Array, Divide and Conquer +1· 64 companies

918. Maximum Sum Circular SubarrayVideo

Solution51.5%Medium

Array, Divide and Conquer +3· 12 companies

978. Longest Turbulent SubarrayVideo

Solution49.6%Medium

Array, Dynamic Programming +1· 3 companies

55. Jump GameVideo

Solution41.2%Medium

Array, Dynamic Programming +1· 33 companies

45. Jump Game IIVideo

Solution43.2%Medium

Array, Dynamic Programming +1· 26 companies

1871. Jump Game VIIVideo

Solution35.4%Medium

Dynamic Programming, Prefix Sum +2· 4 companies

134. Gas StationVideo

Solution48.4%Medium

Array, Greedy· 29 companies

846. Hand of StraightsVideo

Solution58.5%Medium

Array, Greedy +2· 6 companies

649. Dota2 SenateVideo

Solution50.3%Medium

Greedy, Queue +1· 6 companies

1899. Merge Triplets to Form Target TripletVideo

Solution69.5%Medium

Array, Greedy· 1 company

763. Partition LabelsVideo

Solution81.8%Medium

Greedy, Hash Table +2· 9 companies

678. Valid Parenthesis StringVideo

Solution42.8%Medium

Dynamic Programming, Greedy +2· 15 companies

57. Insert IntervalVideo

Solution46.1%Medium

Array· 16 companies

56. Merge IntervalsVideo

Solution52.6%Medium

Array, Sorting· 112 companies

435. Non-overlapping IntervalsVideo

Solution57.5%Medium

Array, Dynamic Programming +2· 18 companies

253. Meeting Rooms IIVideoPremium

Solution52.6%Medium

Array, Greedy +4· 42 companies

2807. Insert Greatest Common Divisors in Linked ListVideo

Solution91.4%Medium

Linked List, Math +1· 4 companies

48. Rotate ImageVideo

Solution80.7%Medium

Array, Math +1· 36 companies

54. Spiral MatrixVideo

Solution58.2%Medium

Array, Matrix +1· 49 companies

73. Set Matrix ZeroesVideo

Solution63.8%Medium

Array, Hash Table +1· 22 companies

50. Pow(x, n)Video

Solution39.0%Medium

Math, Recursion· 22 companies

43. Multiply StringsVideo

Solution44.4%Medium

Math, Simulation +1· 17 companies

2013. Detect SquaresVideo

Solution53.0%Medium

Array, Counting +2· 4 companies

371. Sum of Two IntegersVideo

Solution55.9%Medium

Bit Manipulation, Math· 8 companies

7. Reverse IntegerVideo

Solution32.2%Medium

Math· 22 companies

201. Bitwise AND of Numbers RangeVideo

Solution49.4%Medium

Bit Manipulation· 5 companies

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