Challenges
All Problems
144 problemsBasic100
TITLETAGSDIFFICULTY
Two Sum
ArrayEasyNumber Of Recent Calls
QueueEasyMiddle Of The Linked List
Linked ListEasyLast Stone Weight
HeapEasyLongest Common Prefix
TrieEasyMoving Average From Data Stream
QueueEasyFlood Fill
BFSEasyBinary Tree Postorder Traversal
TreeEasyValid Parentheses
StringEasyContains Duplicate
SetEasyFind the Town Judge
GraphEasyMaximum Depth Of Binary Tree
TreeEasyMerge Two Sorted Lists
Linked ListEasyBinary Tree Preorder Traversal
TreeEasyBinary Tree Inorder Traversal
TreeEasyKth Smallest Element
QuickselectEasyNext Greater Element
Monotonic StackEasyFind If Path Exists in Graph
DFSEasyValid Palindrome
StringEasyRunning Sum of 1d Array
ArrayEasyBaseball Game
StackEasyFind The Index Of The First Occurrence
String MatchingEasyPath Sum
TreeEasyClimbing Stairs
Dynamic ProgrammingEasyMaximum Average Subarray
ArrayEasySearch Insert Position
ArrayEasyValid Anagram
Hash MapEasyBinary Search
ArrayEasyMerge Sorted Array
Two PointersEasyIntersection Of Two Arrays
SetEasyLongest Palindromic Substring
Two PointersMediumRange Sum Query
ArrayMediumCoin Change
ArrayMediumCombination Sum
BacktrackingMediumFind Peak Element
ArrayMediumTop K Frequent Elements
Hash MapMediumCount Good Nodes In Binary Tree
TreeMediumEvaluate Reverse Polish Notation
StackMediumFind All Anagrams In A String
Sliding WindowMediumK Closest Points To Origin
HeapMediumAll Paths From Source to Target
DFSMediumInsert Interval
ArrayMediumKth Smallest Element In A BST
TreeMedium3Sum
ArrayMediumCheapest Flights Within K Stops
DijkstraMediumConnecting Cities With Minimum Cost
MSTMediumGroup Anagrams
Hash MapMediumHouse Robber
ArrayMediumLongest Substring Without Repeating Characters
StringMediumPermutations
BacktrackingMediumCourse Schedule
Topological SortMediumRemove Nth Node From End Of List
Linked ListMediumSearch A 2D Matrix
ArrayMediumUnique Paths
MatrixMediumLargest Number
SortingMediumKth Largest Element In An Array
HeapMediumMerge Intervals
ArrayMediumPartition Equal Subset Sum
ArrayMediumRedundant Connection
Union FindMediumReplace Words
TrieMediumReverse Linked List
Linked ListMediumRotting Oranges
BFSMediumSort Colors
Two PointersMediumBinary Tree Right Side View
TreeMediumLongest Consecutive Sequence
SetMediumWord Break
TrieMediumDaily Temperatures
Monotonic StackMediumSubarray Sum Equals K
ArrayMediumContainer With Most Water
ArrayMediumNumber of Connected Components
DFSMediumKth Largest Element
QuickselectMediumNumber Of Operations To Make Network Connected
Union FindMediumTarget Sum
ArrayMediumValidate Binary Search Tree
TreeMediumMin Cost To Connect All Points
MSTMediumNetwork Delay Time
DijkstraMediumSubsets
BacktrackingMediumDecode String
StackMediumDiameter Of Binary Tree
TreeMediumNumber of Islands
BFSMediumCourse Schedule II
Topological SortMediumIs Graph Bipartite
GraphMediumBinary Tree Level Order Traversal
TreeMediumLongest Common Subsequence
String MatchingMediumSearch A 2D Matrix II
ArrayMediumMinimum Window Substring
StringHardOptimize Water Distribution In A Village
MSTHardPath With Minimum Effort
DijkstraHardThe Earliest Moment When Everyone Become Friends
Union FindHardLast Stone Weight II
ArrayHardWiggle Sort II
QuickselectHardNon-Overlapping Intervals
ArrayHardLargest Rectangle In Histogram
Monotonic StackHardSliding Window Maximum
QueueHardBinary Tree Maximum Path Sum
TreeHardAlien Dictionary
Topological SortHardEdit Distance
String MatchingHardKth Smallest Element In A Sorted Matrix
Binary SearchHardWord Ladder
BFSHardKoko Eating Bananas
ArrayHard