See the algorithm run.
Step through 168 LeetCode problems line by line. Every approach, from brute force to optimal, is animated on your own input.
- 1.Two SumEasy
- 2.Add Two NumbersMedium
- 3.Longest Substring Without Repeating CharactersMedium
- 4.Median of Two Sorted ArraysHard
- 5.Longest Palindromic SubstringMedium
- 7.Reverse IntegerMedium
- 8.String to Integer (atoi)Medium
- 10.Regular Expression MatchingHard
- 11.Container With Most WaterMedium
- 15.3SumMedium
- 17.Letter Combinations of a Phone NumberMedium
- 19.Remove Nth Node From End of ListMedium
- 20.Valid ParenthesesEasy
- 21.Merge Two Sorted ListsEasy
- 22.Generate ParenthesesMedium
- 23.Merge k Sorted ListsHard
- 25.Reverse Nodes in k-GroupHard
- 33.Search in Rotated Sorted ArrayMedium
- 36.Valid SudokuMedium
- 39.Combination SumMedium
- 40.Combination Sum IIMedium
- 42.Trapping Rain WaterHard
- 43.Multiply StringsMedium
- 45.Jump Game IIMedium
- 46.PermutationsMedium
- 48.Rotate ImageMedium
- 49.Group AnagramsMedium
- 50.Pow(x, n)Medium
- 51.N-QueensHard
- 53.Maximum SubarrayMedium
- 54.Spiral MatrixMedium
- 55.Jump GameMedium
- 56.Merge IntervalsMedium
- 57.Insert IntervalMedium
- 62.Unique PathsMedium
- 66.Plus OneEasy
- 67.Add BinaryEasy
- 70.Climbing StairsEasy
- 72.Edit DistanceMedium
- 73.Set Matrix ZeroesMedium
- 74.Search a 2D MatrixMedium
- 75.Sort ColorsMedium
- 76.Minimum Window SubstringHard
- 78.SubsetsMedium
- 79.Word SearchMedium
- 84.Largest Rectangle in HistogramHard
- 90.Subsets IIMedium
- 91.Decode WaysMedium
- 97.Interleaving StringMedium
- 98.Validate Binary Search TreeMedium
- 100.Same TreeEasy
- 102.Binary Tree Level Order TraversalMedium
- 104.Maximum Depth of Binary TreeEasy
- 105.Construct Binary Tree from Preorder and Inorder TraversalMedium
- 110.Balanced Binary TreeEasy
- 115.Distinct SubsequencesHard
- 121.Best Time to Buy and Sell StockEasy
- 124.Binary Tree Maximum Path SumHard
- 125.Valid PalindromeEasy
- 127.Word LadderHard
- 128.Longest Consecutive SequenceMedium
- 130.Surrounded RegionsMedium
- 131.Palindrome PartitioningMedium
- 133.Clone GraphMedium
- 134.Gas StationMedium
- 136.Single NumberEasy
- 138.Copy List with Random PointerMedium
- 139.Word BreakMedium
- 141.Linked List CycleEasy
- 143.Reorder ListMedium
- 146.LRU CacheMedium
- 150.Evaluate Reverse Polish NotationMedium
- 152.Maximum Product SubarrayMedium
- 153.Find Minimum in Rotated Sorted ArrayMedium
- 155.Min StackMedium
- 167.Two Sum II - Input Array Is SortedMedium
- 169.Majority ElementEasy
- 190.Reverse BitsEasy
- 191.Number of 1 BitsEasy
- 198.House RobberMedium
- 199.Binary Tree Right Side ViewMedium
- 200.Number of IslandsMedium
- 202.Happy NumberEasy
- 206.Reverse Linked ListEasy
- 207.Course ScheduleMedium
- 208.Implement Trie (Prefix Tree)Medium
- 210.Course Schedule IIMedium
- 211.Design Add and Search Words Data StructureMedium
- 212.Word Search IIHard
- 213.House Robber IIMedium
- 215.Kth Largest Element in an ArrayMedium
- 217.Contains DuplicateEasy
- 224.Basic CalculatorHard
- 226.Invert Binary TreeEasy
- 230.Kth Smallest Element in a BSTMedium
- 232.Implement Queue using StacksEasy
- 235.Lowest Common Ancestor of a Binary Search TreeMedium
- 236.Lowest Common Ancestor of a Binary TreeMedium
- 238.Product of Array Except SelfMedium
- 239.Sliding Window MaximumHard
- 242.Valid AnagramEasy
- 252.Meeting RoomsPremiumEasy
- 253.Meeting Rooms IIPremiumMedium
- 261.Graph Valid TreePremiumMedium
- 268.Missing NumberEasy
- 269.Alien DictionaryPremiumHard
- 271.Encode and Decode StringsPremiumMedium
- 278.First Bad VersionEasy
- 286.Walls and GatesPremiumMedium
- 287.Find the Duplicate NumberMedium
- 295.Find Median from Data StreamHard
- 297.Serialize and Deserialize Binary TreeHard
- 300.Longest Increasing SubsequenceMedium
- 309.Best Time to Buy and Sell Stock with CooldownMedium
- 310.Minimum Height TreesMedium
- 312.Burst BalloonsHard
- 322.Coin ChangeMedium
- 323.Number of Connected Components in an Undirected GraphPremiumMedium
- 329.Longest Increasing Path in a MatrixHard
- 332.Reconstruct ItineraryHard
- 338.Counting BitsEasy
- 347.Top K Frequent ElementsMedium
- 355.Design TwitterMedium
- 371.Sum of Two IntegersMedium
- 377.Combination Sum IVMedium
- 383.Ransom NoteEasy
- 409.Longest PalindromeEasy
- 416.Partition Equal Subset SumMedium
- 417.Pacific Atlantic Water FlowMedium
- 424.Longest Repeating Character ReplacementMedium
- 435.Non-overlapping IntervalsMedium
- 438.Find All Anagrams in a StringMedium
- 494.Target SumMedium
- 518.Coin Change IIMedium
- 542.01 MatrixMedium
- 543.Diameter of Binary TreeEasy
- 567.Permutation in StringMedium
- 572.Subtree of Another TreeEasy
- 621.Task SchedulerMedium
- 647.Palindromic SubstringsMedium
- 678.Valid Parenthesis StringMedium
- 684.Redundant ConnectionMedium
- 695.Max Area of IslandMedium
- 703.Kth Largest Element in a StreamEasy
- 704.Binary SearchEasy
- 721.Accounts MergeMedium
- 733.Flood FillEasy
- 739.Daily TemperaturesMedium
- 743.Network Delay TimeMedium
- 746.Min Cost Climbing StairsEasy
- 763.Partition LabelsMedium
- 778.Swim in Rising WaterHard
- 787.Cheapest Flights Within K StopsMedium
- 846.Hand of StraightsMedium
- 853.Car FleetMedium
- 875.Koko Eating BananasMedium
- 876.Middle of the Linked ListEasy
- 973.K Closest Points to OriginMedium
- 981.Time Based Key-Value StoreMedium
- 994.Rotting OrangesMedium
- 1046.Last Stone WeightEasy
- 1143.Longest Common SubsequenceMedium
- 1235.Maximum Profit in Job SchedulingHard
- 1448.Count Good Nodes in Binary TreeMedium
- 1584.Min Cost to Connect All PointsMedium
- 1851.Minimum Interval to Include Each QueryHard
- 1899.Merge Triplets to Form Target TripletMedium
- 2013.Detect SquaresMedium