Arrays & Hashing
9 problemsContains DuplicateValid AnagramTwo SumGroup AnagramsTop K Frequent ElementsProduct of Array Except SelfValid SudokuEncode and Decode Strings+1 more
Two Pointers
5 problemsValid PalindromeTwo Sum II3SumContainer With Most WaterTrapping Rain Water
Sliding Window
6 problemsBest Time to Buy and Sell StockLongest Substring Without Repeating CharactersLongest Repeating Character ReplacementPermutation in StringMinimum Window SubstringSliding Window Maximum
Stack
7 problemsValid ParenthesesMin StackEvaluate Reverse Polish NotationGenerate ParenthesesDaily TemperaturesCar FleetLargest Rectangle in Histogram
Binary Search
7 problemsBinary SearchSearch a 2D MatrixKoko Eating BananasFind Minimum in Rotated Sorted ArraySearch in Rotated Sorted ArrayTime Based Key-Value StoreMedian of Two Sorted Arrays
Linked List
11 problemsReverse Linked ListMerge Two Sorted ListsReorder ListRemove Nth Node From EndCopy List with Random PointerAdd Two NumbersLinked List CycleFind the Duplicate Number+3 more
Trees
15 problemsInvert Binary TreeMaximum DepthDiameter of Binary TreeBalanced Binary TreeSame TreeSubtree of Another TreeLCA of BSTLevel Order Traversal+7 more
Tries
3 problemsImplement TrieDesign Add and Search WordsWord Search II
Heap / Priority Queue
7 problemsKth Largest Element in StreamLast Stone WeightK Closest PointsKth Largest Element in ArrayTask SchedulerDesign TwitterFind Median from Data Stream
Backtracking
9 problemsSubsetsCombination SumPermutationsSubsets IICombination Sum IIWord SearchPalindrome PartitioningLetter Combinations+1 more
Graphs
13 problemsNumber of IslandsClone GraphMax Area of IslandPacific AtlanticSurrounded RegionsRotting OrangesWalls and GatesCourse Schedule+5 more
1-D Dynamic Programming
12 problemsClimbing StairsMin Cost Climbing StairsHouse RobberHouse Robber IILongest Palindromic SubstringPalindromic SubstringsDecode WaysCoin Change+4 more
2-D Dynamic Programming
11 problemsUnique PathsLongest Common SubsequenceBest Time to Buy/Sell Stock with CooldownCoin Change IITarget SumInterleaving StringLongest Increasing Path in MatrixDistinct Subsequences+3 more
Greedy
8 problemsMaximum SubarrayJump GameJump Game IIGas StationHand of StraightsMerge TripletsPartition LabelsValid Parenthesis String
Intervals
6 problemsInsert IntervalMerge IntervalsNon-overlapping IntervalsMeeting RoomsMeeting Rooms IIMinimum Interval to Include Each Query
Math & Geometry
8 problemsRotate ImageSpiral MatrixSet Matrix ZeroesHappy NumberPlus OnePow(x, n)Multiply StringsDetect Squares
Bit Manipulation
7 problemsSingle NumberNumber of 1 BitsCounting BitsReverse BitsMissing NumberSum of Two IntegersReverse Integer