Apr 15, 2026
You are given two linked lists: list1 and list2 of sizes n and m respectively. Remove list1’s nodes from the a-th node to the b-th node (0-indexed), and put list2...
leetcodemediumlinked-list
leetcodemediumlinked-listpointer-manipulation
Apr 13, 2026
You are given an array of events where events[i] = [startDay, endDay]. You can attend an event on any single day in the range [startDay, endDay]. You can only attend...
leetcodemediumgreedyheap
leetcodemediumgreedyheapsortingscheduling
Apr 12, 2026
Given an integer n, return a list of all possible full binary trees with n nodes. Each node has value 0. A full binary tree is a tree where every...
leetcodemediumtreerecursionmemoization
leetcodemediumtreerecursionmemoizationdp
Apr 11, 2026
Given an array nums, find two indices i and j (i != j) such that the digit sum of nums[i] equals the digit sum of nums[j], and return the maximum...
leetcodemediumhash-maparray
leetcodemediumhash-maparraygreedy
Apr 10, 2026
You are given a list of tasks to complete in order. Each day you can complete one task. After completing a task of type t, you must wait at least...
leetcodemediumhash-mapsimulation
leetcodemediumhash-mapsimulationgreedy
Apr 9, 2026
Given an integer array nums and an integer k, find the maximum sum among all subarrays of length k that have all distinct elements. Return 0 if no such subarray...
leetcodemediumsliding-windowhash-map
leetcodemediumsliding-windowhash-maparray
Apr 8, 2026
Given a singly linked list, return a random node’s value. Each node must have an equal probability of being chosen.
leetcodemediumlinked-listrandomized
leetcodemediumlinked-listrandomizedreservoir-sampling
Apr 7, 2026
Given a palindromic string palindrome, replace exactly one character to make it not a palindrome, and make the resulting string the lexicographically smallest possible. Return the result, or an empty...
leetcodemediumstringgreedy
leetcodemediumstringgreedy
Apr 6, 2026
You are given a 0-indexed integer array nums of length n. A split at index i is valid if the sum of the first i + 1 elements is greater...
leetcodemediumprefix-sumarray
leetcodemediumprefix-sumarray
Apr 5, 2026
You are given an integer array pref of size n. Find and return the array arr of size n that satisfies:
leetcodemediumbit-manipulationprefix
leetcodemediumbit-manipulationxorprefix
Apr 2, 2026
Given an m x n integer matrix, if an element is 0, set its entire row and column to 0. You must do it in place.
leetcodemediummatrixarray
leetcodemediummatrixarrayin-place
Apr 1, 2026
Given n nodes labeled 0 to n-1 and a list of undirected edges, determine if these edges form a valid tree.
leetcodemediumgraphdsudfs
leetcodemediumgraphdsudfstreecycle-detection
Mar 31, 2026
Given an integer array nums where exactly two elements appear once and all other elements appear exactly twice, find the two elements that appear only once. Return them in any...
leetcodemediumbit-manipulation
leetcodemediumbit-manipulationxor
Mar 30, 2026
You are given n train rides with distances dist[i]. Each train departs at an integer hour, so you must wait until the next whole hour to board the next train...
leetcodemediumbinary-search
leetcodemediumbinary-searchgreedy
Mar 29, 2026
Implement a thread-safe bounded blocking queue with the following methods: BoundedBlockingQueue(int capacity) – initialize with max capacity void enqueue(int element) – add element to the back; blocks if the queue...
leetcodemediumconcurrencydesign
leetcodemediumconcurrencydesignsemaphoreproducer-consumer
Mar 28, 2026
Two different threads will call foo and bar respectively. Design a mechanism so that "foobar" is printed n times by alternating between the two threads: foo always prints first, then...
leetcodemediumconcurrency
leetcodemediumconcurrencymutexcondition-variablemultithreading
Mar 27, 2026
Given an input string s, reverse the order of the words. A word is a sequence of non-space characters. Words are separated by at least one space. Return a string...
leetcodemediumstringtwo-pointers
leetcodemediumstringtwo-pointers
Mar 27, 2026
You are given two strings s and t. String t is generated by randomly shuffling s and then adding one more letter at a random position. Return the letter that...
leetcodeeasybit-manipulationstring
leetcodeeasybit-manipulationxorstringhash
Mar 27, 2026
Given two strings word1 and word2, merge them by adding letters in alternating order, starting with word1. If one string is longer, append the remaining letters at the end.
leetcodeeasystringtwo-pointers
leetcodeeasystringtwo-pointers
Mar 26, 2026
Given a string s representing a list of words, where each letter can be replaced by a group of letters inside braces {a,b,c}, return all possible words in sorted order....
leetcodemediumbacktrackingstring
leetcodemediumbacktrackingstringparsing
Mar 25, 2026
Given a circular integer array nums, find the maximum possible sum of a non-empty subarray. A circular subarray can wrap around the end back to the beginning.
leetcodemediumdparraykadane
leetcodemediumdparraykadane
Mar 24, 2026
You are given a nested list of integers nestedList. Each element is either an integer or a list whose elements may also be integers or other lists. Implement an iterator...
leetcodemediumdesignstackiterator
leetcodemediumdesignstackiterator
Mar 22, 2026
There are n gas stations along a circular route. Station i has gas[i] units of gas. It costs cost[i] units to travel from station i to station i+1. Starting with...
leetcodemediumgreedyarray
leetcodemediumgreedyarray
Mar 21, 2026
Given an array of positive integers nums and an integer k, return the number of contiguous subarrays where the product of all elements is strictly less than k.
leetcodemediumsliding-windowtwo-pointers
leetcodemediumsliding-windowtwo-pointersarray
Mar 20, 2026
You are given an array prices where prices[i] is the price of a stock on day i. Find the maximum profit with as many transactions as you like, subject to:...
leetcodemediumdp
leetcodemediumdpstate-machinestock
Mar 19, 2026
In an infinite chess board with coordinates from -infinity to +infinity, a knight starts at (0, 0). Return the minimum number of moves to reach (x, y).
leetcodemediumbfs
leetcodemediumbfschessshortest-path
Mar 19, 2026
Implement a SnapshotArray that supports: SnapshotArray(int length) – initializes an array of the given length (all zeros) void set(index, val) – sets the element at index to val int snap()...
leetcodemediumdesignbinary-search
leetcodemediumdesignbinary-searchmap
Mar 18, 2026
Design a hit counter that counts the number of hits received in the past 5 minutes (300 seconds).
leetcodemediumdesignqueue
leetcodemediumdesignqueuedequesliding-window
Mar 18, 2026
Given a binary tree, a node X is good if there is no node with a value greater than X on the path from root to X. Return the number...
leetcodemediumtreedfsbfs
leetcodemediumtreedfsbfs
Mar 17, 2026
A company has n employees numbered 0 to n-1. Each employee has exactly one direct manager given in manager[i], except the head of the company (manager[headID] == -1). An employee...
leetcodemediumtreedfsbfs
leetcodemediumtreedfsbfsgraph
Mar 16, 2026
You are given a 2D array intervals where intervals[i] = [left_i, right_i] represents the inclusive interval [left_i, right_i]. Divide the intervals into one or more groups such that no two...
leetcodemediumgreedyheapintervals
leetcodemediumgreedyheapintervalssweep-line
Mar 15, 2026
A gene string is represented by an 8-character string of 'A', 'C', 'G', and 'T'. Given startGene, endGene, and a bank of valid gene strings, return the minimum number of...
leetcodemediumbfsstring
leetcodemediumbfsstringshortest-path
Mar 12, 2026
There are n rooms labeled 0 to n-1. All rooms are locked except room 0. Each room contains a set of keys to other rooms. Given rooms[i] – the set...
leetcodemediumgraphdfsbfs
leetcodemediumgraphdfsbfsreachability
Mar 11, 2026
Given an n x n binary matrix grid, return the length of the shortest clear path from top-left (0,0) to bottom-right (n-1,n-1). A clear path consists of cells with value...
leetcodemediumgraphbfs
leetcodemediumgraphbfsgridshortest-path
Mar 10, 2026
There are n computers numbered 0 to n-1 connected by cables. connections[i] = [a, b] means a cable connects computers a and b. You can remove an existing cable and...
leetcodemediumgraphdsu
leetcodemediumgraphdsuunion-findconnectivity
Mar 10, 2026
Given the head of a singly linked list, return the middle node. If there are two middle nodes, return the second middle node.
leetcodeeasylinked-listtwo-pointers
leetcodeeasylinked-listtwo-pointersslow-fast
Mar 9, 2026
You are given a string s and an array of index pairs pairs where pairs[i] = [a, b] indicates you can swap the characters at indices a and b any...
leetcodemediumstringgraphdsu
leetcodemediumstringgraphdsuunion-findsorting
Mar 8, 2026
You are given an array points where points[i] = [xi, yi] represents a point on the 2D plane. The cost to connect two points is the Manhattan distance: |xi -...
leetcodemediumgraphmstdsu
leetcodemediumgraphmstkruskaldsu
Mar 7, 2026
We can “shift” a string by shifting each character to its successive character (with z wrapping to a). For example, "abc" can be shifted to "bcd", …, "xyz", "yza", "zab"....
leetcodemediumstringhash
leetcodemediumstringhashcanonical-form
Mar 7, 2026
Given two strings ransomNote and magazine, return true if ransomNote can be constructed by using the letters from magazine. Each letter in magazine can only be used once.
leetcodeeasystringhash
leetcodeeasystringhashfrequency-count
Mar 7, 2026
Given two strings s and t, return true if t is an anagram of s, and false otherwise. An anagram uses the exact same characters with the exact same frequencies....
leetcodeeasystringhash
leetcodeeasystringhashsorting
Mar 7, 2026
Given an integer array nums and an integer k, return true if there are two distinct indices i and j such that nums[i] == nums[j] and abs(i - j) <=...
leetcodeeasyarrayhashsliding-window
leetcodeeasyarrayhashsliding-window
Mar 7, 2026
Given an integer array nums, return true if any value appears at least twice, and false if every element is distinct.
leetcodeeasyarrayhash
leetcodeeasyarrayhashsorting
Mar 6, 2026
Given the root of a binary tree and an integer targetSum, return all root-to-leaf paths where the sum of the node values equals targetSum. Each path should be returned as...
leetcodemediumtreedfsbacktracking
leetcodemediumtreedfsbacktracking
Mar 6, 2026
Given the root of a binary tree, return the inorder traversal of its nodes’ values. Inorder visits: left → root → right.
leetcodeeasytreedfs
leetcodeeasytreedfsstackmorris
Mar 6, 2026
Given the root of a binary tree, return the length of the diameter of the tree. The diameter is the length of the longest path between any two nodes (measured...
leetcodeeasytreedfs
leetcodeeasytreedfsrecursion
Mar 6, 2026
Given the root of a binary tree, return the postorder traversal of its nodes’ values. Postorder visits: left → right → root.
leetcodeeasytreedfs
leetcodeeasytreedfsstack
Mar 6, 2026
Given the root of a binary tree, return the preorder traversal of its nodes’ values. Preorder visits: root → left → right.
leetcodeeasytreedfs
leetcodeeasytreedfsstackmorris
Mar 6, 2026
Given the root of a binary tree and an integer targetSum, return true if the tree has a root-to-leaf path such that adding up all the values along the path...
leetcodeeasytreedfs
leetcodeeasytreedfsrecursion
Mar 6, 2026
Given a binary tree, determine if it is height-balanced. A height-balanced binary tree is one in which the depth of the two subtrees of every node never differs by more...
leetcodeeasytreedfs
leetcodeeasytreedfsrecursion
Mar 5, 2026
Given an integer array nums of unique elements, return all possible subsets (the power set). The solution must not contain duplicate subsets.
leetcodemediumbacktracking
leetcodemediumbacktrackingdfsbit-manipulation
Mar 4, 2026
Given an integer array nums and an integer k, return true if nums has a good subarray, i.e., a contiguous subarray of length at least 2 whose sum is a...
leetcodemediumprefix-sumhash
leetcodemediumprefix-sumhashmath
Mar 4, 2026
Design a Tic-Tac-Toe game that is played on an n x n board between two players. A move is guaranteed to be valid and is placed on an empty block....
leetcodemediumdesignmatrix
leetcodemediumdesignmatrixsimulation
Mar 4, 2026
Given two numbers hour and minutes, return the smaller angle (in degrees) formed between the hour and the minute hand of a clock.
leetcodemediummath
leetcodemediummathgeometry
Mar 4, 2026
Tic-tac-toe is played on a 3 x 3 grid by two players A and B. Player A always plays first. Given an array moves where moves[i] = [row, col] indicates...
leetcodeeasysimulationmatrix
leetcodeeasysimulationmatrixdesign
Feb 18, 2026
Given a positive integer n, generate an n × n matrix filled with elements from 1 to n² in spiral order (clockwise).
leetcodemediummatrixsimulation
leetcodemediummatrixsimulationspiral
Feb 17, 2026
Given two non-negative integers represented as strings num1 and num2, return their product as a string. You cannot convert the inputs to integers directly (numbers can be very large).
leetcodemediumstringmathsimulation
leetcodemediumstringmathbig-integersimulation
Feb 17, 2026
Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining.
leetcodehardtwo-pointersstackdp
leetcodehardtwo-pointersmonotonic-stackprefix-suffixdp
Feb 16, 2026
The count-and-say sequence is a sequence of digit strings defined by the recursive formula:
leetcodemediumstringsimulation
leetcodemediumstringsimulationrun-length-encoding
Feb 15, 2026
You are given an array of k linked lists, each sorted in ascending order. Merge all the linked lists into one sorted linked list and return it.
leetcodehardlinked-listdivide-and-conquerheap
leetcodehardlinked-listdivide-and-conquerheapmerge
Feb 15, 2026
Two strings are special-equivalent if you can swap characters at even indices among themselves and swap characters at odd indices among themselves, any number of times. Return the number of...
leetcodeeasystringhash
leetcodeeasystringhashcanonical-form
Feb 14, 2026
Determine if a 9 x 9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules:
leetcodemediummathbit-manipulation
leetcodemediumbitmaskgridhash
Feb 14, 2026
Given two integers dividend and divisor, divide two integers without using multiplication, division, and mod operator. Return the quotient after dividing dividend by divisor. The integer division should truncate toward...
leetcodemediummathbit-manipulation
leetcodemediumbit-manipulationmath
Feb 12, 2026
Problem
leetcodemediumsliding-windowmonotonic-queue
leetcodemediumsliding-windowmonotonic-queue
Feb 11, 2026
Given an integer array nums, return true if you can partition the array into two subsets such that the sum of the elements in both subsets is equal or false...
leetcodemediumdynamic-programming
leetcodemediumdpknapsack
Feb 11, 2026
Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.
leetcodemediumstack
leetcodemediumstackdata-structure-design
Feb 10, 2026
Problem Statement
leetcodemediumgraphshortest-pathdijkstragrid
leetcodemediumgraphshortest-pathdijkstragrid
Feb 10, 2026
Problem Statement
leetcodemediumgraphshortest-pathdijkstragrid
leetcodemediumgraphshortest-pathdijkstragrid
Feb 9, 2026
91. Decode Ways
leetcodemediumdynamic-programming
leetcodemediumdynamic-programmingstring
Feb 9, 2026
1944. Number of Visible People in a Queue
leetcodehardstackmonotonic-stack
leetcodehardstackmonotonic-stack
Feb 8, 2026
3112. Minimum Time to Visit Disappearing Nodes
leetcodemediumgraphshortest-pathdijkstra
leetcodemediumgraphshortest-pathdijkstra
Feb 8, 2026
210. Course Schedule II
leetcodemediumgraphtopological-sort
leetcodemediumgraphtopological-sort
Feb 7, 2026
1488. Avoid Flood in The City
leetcodemediumarraygreedybinary-searchset
leetcodemediumarraygreedybinary-searchset
Feb 6, 2026
875. Koko Eating Bananas
leetcodemediumarraybinary-search
leetcodemediumarraybinary-search
Feb 6, 2026
532. K-diff Pairs in an Array
leetcodemediumarrayhash-table
leetcodemediumarrayhash-table
Feb 6, 2026
3439. Reschedule Meetings for Maximum Free Time I
leetcodemediumarrayintervalssliding-windowprefix-sum
leetcodemediumarrayintervalssliding-windowprefix-sum
Feb 6, 2026
252. Meeting Rooms
leetcodeeasyarraysortingintervals
leetcodeeasyarraysortingintervals
Feb 5, 2026
1109. Corporate Flight Bookings
leetcodemediumarrayprefix-sumdifference-array
leetcodemediumarrayprefix-sumdifference-array
Feb 4, 2026
787. Cheapest Flights Within K Stops
leetcodemediumgraphshortest-pathdynamic-programmingbellman-ford
leetcodemediumgraphshortest-pathdynamic-programmingbellman-ford
Feb 3, 2026
743. Network Delay Time
leetcodemediumgraphshortest-pathdijkstra
leetcodemediumgraphshortest-pathdijkstra
Feb 2, 2026
974. Subarray Sums Divisible by K
leetcodemediumarrayhash-tableprefix-sum
leetcodemediumarrayhash-tableprefix-sum
Feb 2, 2026
843. Guess the Word
leetcodehardarraystringinteractiveminmax
leetcodehardarraystringinteractiveminmax
Feb 1, 2026
560. Subarray Sum Equals K
leetcodemediumarrayhash-tableprefix-sum
leetcodemediumarrayhash-tableprefix-sum
Feb 1, 2026
325. Maximum Size Subarray Sum Equals k
leetcodemediumarrayhash-tableprefix-sum
leetcodemediumarrayhash-tableprefix-sum
Feb 1, 2026
44. Wildcard Matching
leetcodehardstringdynamic-programminggreedytwo-pointers
leetcodehardstringdynamic-programminggreedytwo-pointers
Jan 30, 2026
981. Time Based Key-Value Store
leetcodemediumhash-tablebinary-searchdesign
leetcodemediumhash-tablebinary-searchdesign
Jan 30, 2026
34. Find First and Last Position of Element in Sorted Array
leetcodemediumarraybinary-search
leetcodemediumarraybinary-search
Jan 30, 2026
162. Find Peak Element
leetcodemediumarraybinary-search
leetcodemediumarraybinary-search
Jan 30, 2026
35. Search Insert Position
leetcodeeasyarraybinary-search
leetcodeeasyarraybinary-search
Jan 29, 2026
739. Daily Temperatures
leetcodemediumarraystackmonotonic-stack
leetcodemediumarraystackmonotonic-stack
Jan 28, 2026
2080. Range Frequency Queries
leetcodemediumarrayhash-mapbinary-searchdesign
leetcodemediumarrayhash-mapbinary-searchdesign
Jan 27, 2026
238. Product of Array Except Self
leetcodemediumarrayprefix-sumtwo-pointers
leetcodemediumarrayprefix-sumtwo-pointers
Jan 27, 2026
1136. Parallel Courses
leetcodehardgraphtopological-sortdfsdynamic-programming
leetcodehardgraphtopological-sortdfsdynamic-programmingmemoization
Jan 26, 2026
209. Minimum Size Subarray Sum
leetcodemediumarraysliding-windowbinary-searchprefix-sum
leetcodemediumarraysliding-windowbinary-searchprefix-sumtwo-pointers
Jan 26, 2026
862. Shortest Subarray with Sum at Least K
leetcodehardarraysliding-windowdequeprefix-summonotonic-deque
leetcodehardarraysliding-windowdequeprefix-summonotonic-deque
Jan 26, 2026
27. Remove Element
leetcodeeasyarraytwo-pointers
leetcodeeasyarraytwo-pointersin-place
Jan 25, 2026
354. Russian Doll Envelopes
leetcodemediumarraydynamic-programmingbinary-searchsorting
leetcodemediumarraydynamic-programmingbinary-searchsortinglongest-increasing-subsequence
Jan 25, 2026
213. House Robber II
leetcodemediumarraydynamic-programming
leetcodemediumarraydynamic-programmingdpcircular-array
Jan 24, 2026
622. Design Circular Queue
leetcodemediumarraylinked-listdesignqueue
leetcodemediumarraylinked-listdesignqueuecircular-queuedata-structure
Jan 23, 2026
1233. Remove Sub-Folders from the Filesystem
leetcodemediumarraystringtriesorting
leetcodemediumarraystringtriesortingprefix-matching
Jan 22, 2026
1801. Number of Orders in the Backlog
leetcodemediumarrayheappriority-queuesimulation
leetcodemediumarrayheappriority-queuesimulationgreedy
Jan 21, 2026
63. Unique Paths II
leetcodemediumarraydynamic-programmingmatrix
leetcodemediumarraydynamic-programmingmatrixgridobstacles
Jan 20, 2026
498. Diagonal Traverse
leetcodemediumarraymatrixsimulation
leetcodemediumarraymatrixsimulation
Jan 20, 2026
189. Rotate Array
leetcodemediumarray
leetcodemediumarrayrotationtwo-pointers
Jan 20, 2026
Minimal, copy-paste C++ for binary search, rotated arrays, 2D search, and answer-space search. Matches Data Structures lower/upper bound style.
leetcodetemplatessearchbinary-search
leetcodetemplatessearchbinary-searchdivide-and-conquer
Jan 20, 2026
327. Count of Range Sum
leetcodehardarraydivide-and-conquer
leetcodehardarraydivide-and-conquermerge-sortsegment-treeprefix-sum
Jan 19, 2026
236. Lowest Common Ancestor of a Binary Tree
leetcodemediumtreedfs
leetcodemediumtreedfsrecursionlca
Jan 19, 2026
211. Design Add and Search Words Data Structure
leetcodemediumstringdesigntrie
leetcodemediumstringdesigntriewildcard-searchdfs
Jan 19, 2026
1701. Average Waiting Time
leetcodemediumarraysimulation
leetcodemediumarraysimulationgreedy
Jan 19, 2026
645. Set Mismatch
leetcodeeasyarrayhash-tablemath
leetcodeeasyarrayhash-tablemathbit-manipulationnegative-marking
Jan 19, 2026
409. Longest Palindrome
leetcodeeasystringhash-tablegreedy
leetcodeeasystringhash-tablegreedybit-manipulationpalindrome
Jan 19, 2026
387. First Unique Character in a String
leetcodeeasystringhash-table
leetcodeeasystringhash-tablebit-manipulationfrequency-counting
Jan 19, 2026
349. Intersection of Two Arrays
leetcodeeasyarrayhash-table
leetcodeeasyarrayhash-tabletwo-pointerssorting
Jan 19, 2026
226. Invert Binary Tree
leetcodeeasytreedfs
leetcodeeasytreedfsrecursion
Jan 19, 2026
2185. Counting Words With a Given Prefix
leetcodeeasystringarray
leetcodeeasystringarrayprefixsimulation
Jan 19, 2026
1624. Largest Substring Between Two Equal Characters
leetcodeeasystringhash-table
leetcodeeasystringhash-tablesubstringtwo-pointers
Jan 19, 2026
112. Path Sum
leetcodeeasytreedfs
leetcodeeasytreedfsrecursionbacktracking
Jan 19, 2026
111. Minimum Depth of Binary Tree
leetcodeeasytreedfs
leetcodeeasytreedfsbfsrecursion
Jan 19, 2026
104. Maximum Depth of Binary Tree
leetcodeeasytreedfs
leetcodeeasytreedfsbfsrecursion
Jan 19, 2026
101. Symmetric Tree
leetcodeeasytreedfs
leetcodeeasytreedfsrecursion
Jan 19, 2026
100. Same Tree
leetcodeeasytreedfs
leetcodeeasytreedfsrecursion
Jan 19, 2026
211. Design Add and Search Words Data Structure
leetcodemediumstringdesigntrie
leetcodemediumstringdesigntriewildcard-searchdfs
Jan 19, 2026
409. Longest Palindrome
leetcodeeasystringhash-tablegreedy
leetcodeeasystringhash-tablegreedybit-manipulationpalindrome
Jan 18, 2026
208. Implement Trie (Prefix Tree)
leetcodemediumstringdesigntrie
leetcodemediumstringdesigntrieprefix-treedata-structure
Jan 18, 2026
732. My Calendar III
leetcodehardarraybinary-searchdesignsegment-treeordered-set
leetcodehardarraybinary-searchdesignsegment-treelazy-propagationsweep-linedifference-array
Jan 18, 2026
3110. Score of a String
leetcodeeasystringarray
leetcodeeasystringarraysimulationascii
Jan 17, 2026
729. My Calendar I
leetcodemediumarraybinary-searchdesignordered-set
leetcodemediumarraybinary-searchdesignordered-setintervaloverlap-detection
Jan 17, 2026
315. Count of Smaller Numbers After Self
leetcodehardarraybinary-searchdivide-and-conquerbinary-indexed-treesegment-treemerge-sort
leetcodehardarrayfenwick-treebinary-indexed-treecoordinate-compressioninversion-count
Jan 16, 2026
3477. Number of Unplaced Fruits
leetcodemediumarraygreedysegment-tree
leetcodemediumarraygreedysegment-treedata-structure
Jan 16, 2026
307. Range Sum Query - Mutable
leetcodemediumarraysegment-treebinary-indexed-tree
leetcodemediumarraysegment-treebinary-indexed-treedata-structure
Jan 16, 2026
305. Number of Islands II
leetcodehardarrayunion-findgraph
leetcodehardarrayunion-finddisjoint-setincrementaldynamic
Jan 15, 2026
802. Find Eventual Safe States
leetcodemediumgraphdfscycle-detection
leetcodemediumgraphdfscycle-detectionthree-state-coloring
Jan 15, 2026
315. Count of Smaller Numbers After Self
leetcodehardarraybinary-searchdivide-and-conquerbinary-indexed-treesegment-treemerge-sort
leetcodehardarrayfenwick-treebinary-indexed-treecoordinate-compressioninversion-count
Jan 14, 2026
LCR 113. Course Schedule II
leetcodemediumgraphtopological-sortdfs
leetcodemediumgraphtopological-sortdfscycle-detection
Jan 14, 2026
310. Minimum Height Trees
leetcodemediumgraphtreetopological-sortbfs
leetcodemediumgraphtreetopological-sortbfspeeling-leaves
Jan 14, 2026
269. Alien Dictionary
leetcodehardgraphtopological-sortstring
leetcodehardgraphtopological-sortstringbfskahn
Jan 13, 2026
1670. Design Front Middle Back Queue
leetcodemediumdesigndequedata-structure
leetcodemediumdesigndequedata-structuretwo-deques
Jan 12, 2026
79. Word Search
leetcodemediumarraybacktrackingmatrixdfs
leetcodemediumarraybacktrackingmatrixdfsrecursion
Jan 12, 2026
22. Generate Parentheses
leetcodemediumstringbacktrackingrecursion
leetcodemediumstringbacktrackingrecursiondfs
Jan 12, 2026
51. N-Queens
leetcodehardarraybacktrackingrecursion
leetcodehardarraybacktrackingrecursionconstraint-satisfaction
Jan 12, 2026
844. Backspace String Compare
leetcodeeasystringtwo-pointersstack
leetcodeeasystringtwo-pointersstacksimulation
Jan 11, 2026
721. Accounts Merge
leetcodemediumarrayhash-tablestringunion-finddfs
leetcodemediumarrayhash-tablestringunion-finddisjoint-setdfs
Jan 10, 2026
64. Minimum Path Sum
leetcodemediumarraydynamic-programmingmatrix
leetcodemediumarraydynamic-programmingmatrixgrid
Jan 10, 2026
1340. Jump Game V
leetcodehardarraydynamic-programmingdfsmemoization
leetcodehardarraydynamic-programmingdfsmemoizationrecursion
Jan 9, 2026
673. Number of Longest Increasing Subsequence
leetcodemediumarraydynamic-programming
leetcodemediumarraydynamic-programminglongest-increasing-subsequence
Jan 8, 2026
692. Top K Frequent Words
leetcodemediumhash-tableheapsortingstring
leetcodemediumhash-tableheapsortingstringpriority-queue
Jan 8, 2026
5. Longest Palindromic Substring
leetcodemediumstringtwo-pointersdynamic-programming
leetcodemediumstringtwo-pointerspalindromeexpand-around-centermanacher
Jan 7, 2026
429. N-ary Tree Level Order Traversal
leetcodemediumtreebfsn-ary-tree
leetcodemediumtreebfslevel-order-traversaln-ary-tree
Jan 7, 2026
323. Number of Connected Components in an Undirected Graph
leetcodemediumgraphbfsdfsunion-find
leetcodemediumgraphbfsconnected-componentsundirected-graph
Jan 7, 2026
102. Binary Tree Level Order Traversal
leetcodemediumtreebfsbinary-tree
leetcodemediumtreebfslevel-order-traversalbinary-tree
Jan 7, 2026
993. Cousins in Binary Tree
leetcodeeasytreebfsbinary-tree
leetcodeeasytreebfsbinary-treelevel-order-traversal
Jan 6, 2026
103. Binary Tree Zigzag Level Order Traversal
leetcodemediumtreebfsbinary-tree
leetcodemediumtreebfslevel-order-traversaldequebinary-tree
Jan 5, 2026
215. Kth Largest Element in an Array
leetcodemediumarrayheapquickselectdivide-and-conquer
leetcodemediumarrayheappriority-queuequickselectdivide-and-conquersorting
Jan 5, 2026
Minimal, copy-paste C++ for min/max heap, K-way merge, top K, and two heaps. See also Data Structures for heap patterns.
leetcodetemplatesheappriority-queue
leetcodetemplatesheappriority-queuedata-structures
Jan 4, 2026
53. Maximum Subarray
leetcodemediumarraydynamic-programminggreedydivide-and-conquer
Jan 4, 2026
376. Wiggle Subsequence
leetcodemediumarraydynamic-programminggreedy
Jan 4, 2026
1605. Find Valid Matrix Given Row and Column Sums
leetcodemediumarraymatrixgreedy
Jan 4, 2026
1400. Construct K Palindrome Strings
leetcodemediumstringgreedyhash-table
Jan 4, 2026
1247. Minimum Swaps to Make Strings Equal
leetcodemediumstringmathgreedy
Jan 4, 2026
1029. Two City Scheduling
leetcodemediumarraygreedysorting
Jan 4, 2026
135. Candy
leetcodehardarraygreedy
Jan 4, 2026
1710. Maximum Units on a Truck
leetcodeeasyarraygreedysorting
Jan 4, 2026
1217. Minimum Cost to Move Chips to The Same Position
leetcodeeasyarraymathgreedy
Jan 3, 2026
561. Array Partition
leetcodeeasyarraygreedysorting
Jan 3, 2026
122. Best Time to Buy and Sell Stock II
leetcodemediumarraygreedydynamic-programming
Jan 3, 2026
392. Is Subsequence
leetcodeeasystringtwo-pointersgreedydynamic-programming
Jan 3, 2026
55. Jump Game
leetcodemediumarraygreedydynamic-programming
Jan 3, 2026
452. Minimum Number of Arrows to Burst Balloons
leetcodemediumarraygreedysortingintervals
Jan 3, 2026
435. Non-overlapping Intervals
leetcodemediumarraygreedysortingintervalsdynamic-programming
Jan 3, 2026
860. Lemonade Change
leetcodeeasyarraygreedysimulation
Jan 3, 2026
455. Assign Cookies
leetcodeeasyarraygreedysortingtwo-pointers
Jan 2, 2026
351. Android Unlock Patterns
leetcodemediumbacktrackingrecursiondynamic-programming
Jan 1, 2026
1177. Can Make Palindrome from Substring
leetcodemediumstringbit-manipulationprefix-sumhash-table
Jan 1, 2026
303. Range Sum Query - Immutable
leetcodeeasyarraydesignprefix-sum
Jan 1, 2026
393. UTF-8 Validation
leetcodemediumbit-manipulationstringarray
Jan 1, 2026
308. Range Sum Query 2D - Mutable
leetcodeharddesigndata-structuresprefix-summatrix
Jan 1, 2026
568. Maximum Vacation Days
leetcodeharddynamic-programminggraphoptimization
Jan 1, 2026
418. Sentence Screen Fitting
leetcodemediumdynamic-programmingstringsimulation
Jan 1, 2026
496. Next Greater Element I
leetcodeeasyarraystackmonotonic-stackhash-table
Jan 1, 2026
360. Sort Transformed Array
leetcodemediumarraytwo-pointersmathparabola
Dec 31, 2025
715. Range Module
leetcodeharddesigndata-structuresintervalmaptree-map
Dec 31, 2025
425. Word Squares
leetcodehardbacktrackingtrierecursionstring
Dec 31, 2025
270. Closest Binary Search Tree Value
leetcodeeasybinary-search-treetreerecursionbinary-search
Dec 31, 2025
685. Redundant Connection II
leetcodehardunion-finddsugraphcycle-detectiondirected-graph
Dec 31, 2025
285. Inorder Successor in BST
leetcodemediumbinary-search-treetreeinorder-traversal
Dec 31, 2025
487. Max Consecutive Ones II
leetcodemediumarraydynamic-programmingsliding-window
Dec 31, 2025
661. Image Smoother
leetcodeeasymatrixarraysimulation
Dec 31, 2025
616. Add Bold Tag in String
leetcodemediumstringarraygreedy
Dec 30, 2025
681. Next Closest Time
leetcodemediumstringsimulationbrute-force
Dec 30, 2025
683. K Empty Slots
leetcodemediumsliding-windowtwo-pointersarray
Dec 30, 2025
686. Repeated String Match
leetcodemediumstring-matchingkmprabin-karprolling-hash
Dec 29, 2025
684. Redundant Connection
leetcodemediumunion-finddsugraphcycle-detectiondfs
Dec 28, 2025
1976. Number of Ways to Arrive at Destination
leetcodemediumdijkstrashortest-pathgraphdynamic-programming
Dec 18, 2025
[Medium] 547. Number of Provinces
leetcodealgorithmmediumcppdisjoint-setdfsgraphproblem-solving
Dec 17, 2025
[Medium] 399. Evaluate Division
leetcodealgorithmmediumcppdisjoint-setgraphdfsproblem-solving
Dec 16, 2025
[Medium] 690. Employee Importance
leetcodealgorithmmediumcppdfsbfshash-tableproblem-solving
Dec 16, 2025
[Hard] 850. Rectangle Area II
leetcodealgorithmhardcppgeometrysweep-linesegment-treeproblem-solving
Dec 14, 2025
[Medium] 286. Walls and Gates
leetcodealgorithmmediumcpparraymatrixbfsproblem-solving
Dec 14, 2025
[Medium] 279. Perfect Squares
leetcodealgorithmmediumcppmathdynamic-programmingbfsproblem-solving
Dec 14, 2025
Minimal, copy-paste C++ for interval scheduling, activity selection, and greedy on arrays/strings with sorting.
leetcodetemplatesgreedy
leetcodetemplatesgreedyalgorithms
Dec 14, 2025
[Easy] 346. Moving Average from Data Stream
leetcodealgorithmeasycppqueuesliding-windowdesignproblem-solving
Dec 13, 2025
[Medium] 994. Rotting Oranges
leetcodealgorithmmediumcpparraymatrixbfsproblem-solving
Dec 11, 2025
[Medium] 253. Meeting Rooms II
leetcodealgorithmmediumcpparraysortingpriority-queuetwo-pointersproblem-solving
Dec 11, 2025
[Easy] 67. Add Binary
leetcodealgorithmeasycppstringmathbit-manipulationproblem-solving
Dec 10, 2025
[Medium] 281. Zigzag Iterator
leetcodealgorithmmediumcppdesigniteratorproblem-solving
Dec 3, 2025
[Hard] 1206. Design Skiplist
leetcodealgorithmhardcppdata-structuresskiplistlinked-listproblem-solving
Dec 2, 2025
[Medium] 75. Sort Colors
leetcodealgorithmmediumcpparraytwo-pointerssortingproblem-solving
Dec 2, 2025
[Medium] 593. Valid Square
leetcodealgorithmmediumcppmathgeometryproblem-solving
Dec 2, 2025
[Medium] 146. LRU Cache
leetcodealgorithmmediumcppdesigndata-structureshash-maplinked-listproblem-solving
Dec 2, 2025
[Medium] 146. LRU Cache
leetcodealgorithmmediumcppdesigndata-structureshash-maplinked-listproblem-solving
Nov 24, 2025
[Medium] Round Trip Ticket Cost Minimization
algorithmmediumcpparrayoptimizationproblem-solving
algorithmmediumarrayoptimizationgreedytwo-pointers
Nov 24, 2025
[Medium] 983. Minimum Cost For Tickets
leetcodealgorithmmediumcppdynamic-programmingproblem-solving
leetcodemediumdynamic-programmingdpoptimization
Nov 24, 2025
[Medium] 647. Palindromic Substrings
leetcodealgorithmmediumcppstringtwo-pointersproblem-solving
leetcodemediumstringtwo-pointerspalindromeexpand-around-center
Nov 24, 2025
[Medium] 56. Merge Intervals
leetcodealgorithmmediumcpparraysortingintervalproblem-solving
leetcodemediumarraysortingintervalsmerge
Nov 24, 2025
[Medium] 528. Random Pick with Weight
leetcodealgorithmmediumcppdesignbinary-searchprefix-sumproblem-solving
leetcodemediumdesignbinary-searchprefix-sumweighted-random
Nov 24, 2025
[Medium] 398. Random Pick Index
leetcodealgorithmmediumcpphash-tablereservoir-samplingproblem-solving
leetcodemediumhash-tablereservoir-samplingdesignrandomization
Nov 24, 2025
[Medium] 277. Find the Celebrity
leetcodealgorithmmediumcppgraphtwo-pointersproblem-solving
leetcodemediumgraphtwo-pointerscelebrity
Nov 24, 2025
[Medium] 1762. Buildings With an Ocean View
leetcodealgorithmmediumcpparraystackmonotonic-stackproblem-solving
leetcodemediumarraystackmonotonic-stackgreedytwo-pointers
Nov 24, 2025
[Medium] 129. Sum Root to Leaf Numbers
leetcodealgorithmmediumcpptreedfsproblem-solving
leetcodemediumtreedfsrecursionbinary-tree
Nov 24, 2025
[Medium] 1209. Remove All Adjacent Duplicates in String II
leetcodealgorithmmediumcppstringstacktwo-pointersproblem-solving
leetcodemediumstringstacktwo-pointersin-place
Nov 24, 2025
[Hard] 489. Robot Room Cleaner
leetcodealgorithmhardcppdfsbacktrackingproblem-solving
leetcodeharddfsbacktrackingrobotsimulation
Nov 24, 2025
[Hard] 32. Longest Valid Parentheses
leetcodealgorithmhardcppstringdynamic-programmingstackproblem-solving
leetcodehardstringdynamic-programmingstacktwo-pointersgreedy
Nov 24, 2025
[Easy] 938. Range Sum of BST
leetcodealgorithmeasycpptreebstdfsproblem-solving
leetcodeeasytreebstdfsrecursion
Nov 24, 2025
[Easy] 408. Valid Word Abbreviation
leetcodealgorithmeasycppstringtwo-pointersproblem-solving
leetcodeeasystringtwo-pointersparsing
Nov 24, 2025
[Easy] 1047. Remove All Adjacent Duplicates In String
leetcodealgorithmeasycppstringstacktwo-pointersproblem-solving
leetcodeeasystringstacktwo-pointersin-place
Nov 24, 2025
Minimal, copy-paste C++ for sliding window, two pointers, string matching, manipulation, and parsing. See also Arrays & Strings for KMP and rolling hash.
leetcodetemplatesstring
leetcodetemplatesstringalgorithms
Nov 24, 2025
Minimal, copy-paste C++ for BFS queue, monotonic queue, priority queue, circular queue, and deque. See also Graph and Data Structures (monotonic queue).
leetcodetemplatesqueue
leetcodetemplatesqueuedata-structures
Nov 24, 2025
Minimal, copy-paste C++ for bit operations, fast exponentiation, GCD/LCM, primes, and number theory. See also Math & Geometry.
leetcodetemplatesmathbit-manipulation
leetcodetemplatesmathbit-manipulation
Nov 24, 2025
Minimal, copy-paste C++ for traversal, two pointers, dummy node, reversal, merge, cycle detection, and circular list.
leetcodetemplateslinked-list
leetcodetemplateslinked-list
Nov 24, 2025
Minimal, copy-paste C++ for graph DFS, grid DFS, tree DFS, memoization, and iterative DFS. See also Graph and Backtracking.
leetcodetemplatesdfsgraph
leetcodetemplatesdfsgraphtraversal
Nov 24, 2025
Minimal, copy-paste C++ for LRU/LFU cache, Trie, time-based key-value store, and common design patterns.
leetcodetemplatesdesign
leetcodetemplatesdesigndata-structures
Nov 24, 2025
Minimal, copy-paste C++ for graph and grid BFS, multi-source BFS, shortest path, and level-order traversal. See also Graph for Dijkstra and 0-1 BFS.
leetcodetemplatesbfsgraph
leetcodetemplatesbfsgraphtraversal
Nov 24, 2025
Minimal, copy-paste C++ for permutations, combinations, subsets, combination sum, grid pathfinding, and constraint satisfaction (N-Queens, Sudoku).
leetcodetemplatesbacktracking
leetcodetemplatesbacktrackingdfs
Nov 24, 2025
Minimal, copy-paste C++ for two pointers, sliding window, prefix sum, binary search, and matrix operations. See also Arrays & Strings and Search.
leetcodetemplatesarraymatrix
leetcodetemplatesarraymatrix
Nov 20, 2025
[Medium] 200. Number of Islands
leetcodealgorithmmediumcppdfsgraphmatrixproblem-solving
leetcodemediumdfsgraphmatrixconnected-components
Nov 18, 2025
[Medium] 969. Pancake Sorting
leetcodealgorithmmediumcpparraysortingproblem-solving
leetcodemediumarraysortinggreedypancake-flip
Nov 18, 2025
[Medium] 49. Group Anagrams
leetcodealgorithmmediumcppstringhash-tableproblem-solving
leetcodemediumstringhash-tableanagramcounting
Nov 18, 2025
[Medium] 45. Jump Game II
leetcodealgorithmmediumcpparraygreedyproblem-solving
leetcodemediumarraygreedybfsoptimization
Nov 18, 2025
[Medium] 2. Add Two Numbers
leetcodealgorithmmediumcpplinked-listrecursionproblem-solving
leetcodemediumlinked-listrecursionmathcarry
Nov 18, 2025
[Medium] 198. House Robber
leetcodealgorithmmediumcppdynamic-programmingdpproblem-solving
leetcodemediumdynamic-programmingdparrayoptimization
Nov 18, 2025
[Easy] 509. Fibonacci Number
leetcodealgorithmeasycppdynamic-programmingrecursionproblem-solving
leetcodeeasydynamic-programmingrecursionmathfibonacci
Nov 18, 2025
[Easy] 203. Remove Linked List Elements
leetcodealgorithmeasycpplinked-listiterationproblem-solving
leetcodeeasylinked-listtwo-pointersdummy-node
Nov 17, 2025
[Medium] 1424. Diagonal Traverse II
leetcodealgorithmmediumcpparraymatrixhash-mapbfsproblem-solving
Nov 16, 2025
[Easy] 206. Reverse Linked List
leetcodealgorithmeasycpplinked-listrecursioniterationproblem-solving
Nov 15, 2025
[Medium] 146. LRU Cache
leetcodealgorithmmediumcppdesigndata-structureshash-maplinked-listproblem-solving
Nov 14, 2025
[Medium] 93. Restore IP Addresses
leetcodealgorithmmediumcppbacktrackingstringproblem-solving
Nov 14, 2025
[Hard] 460. LFU Cache
leetcodealgorithmhardcppdesigndata-structureshash-maplinked-listproblem-solving
Nov 14, 2025
Minimal, copy-paste C++ for parentheses matching, expression evaluation, nested structures, and monotonic stack.
leetcodetemplatesstackdata-structures
leetcodetemplatesstackdata-structures
Nov 14, 2025
Minimal, copy-paste C++ for expression evaluation with +, −, ×, ÷ and parentheses. See also Stack for RPN and nested expressions.
leetcodetemplatescalculatorexpression-evaluation
leetcodetemplatescalculatorexpression-evaluationstack
Nov 14, 2025
[Medium] 224. Basic Calculator
leetcodealgorithmmediumcppstringstackexpression-evaluationproblem-solving
leetcodemediumstringstackcalculatorexpression-evaluationparentheses
Nov 14, 2025
[Hard] 772. Basic Calculator III
leetcodealgorithmhardcppstringstackrecursionexpression-evaluationproblem-solving
leetcodehardstringstackcalculatorrecursionexpression-evaluationparentheses
Nov 14, 2025
[Medium] 227. Basic Calculator II
leetcodealgorithmmediumcppstringstackexpression-evaluationproblem-solving
leetcodemediumstringstackcalculatorexpression-evaluation
Nov 5, 2025
[Medium] 324. Wiggle Sort II
leetcodealgorithmmediumcpparraysnth-elementthree-way-partitionindex-mappingproblem-solving
leetcodemediumarraywigglenth_elementpartition
Nov 5, 2025
[Medium] 921. Minimum Add to Make Parentheses Valid
leetcodealgorithmmediumcppstringstackgreedyproblem-solving
leetcodemediumstringstackparenthesesgreedycounting
Nov 5, 2025
[Easy] 20. Valid Parentheses
leetcodealgorithmeasycppstringstackproblem-solving
leetcodeeasystringstackparenthesesvalidation
Nov 5, 2025
[Medium] 525. Contiguous Array
leetcodealgorithmmediumcpparrayshash-mapprefix-sumproblem-solving
leetcodemediumarrayhash-mapprefix-sumsubarray
Nov 5, 2025
[Hard] 480. Sliding Window Median
leetcodealgorithmhardcpparraysmultisetsliding-windowtwo-heapsproblem-solving
leetcodehardarraymultisetsliding-windowtwo-heapsmedian
Nov 5, 2025
[Hard] 239. Sliding Window Maximum
leetcodealgorithmhardcpparraysdequesliding-windowmonotonic-queueproblem-solving
leetcodehardarraydequesliding-windowmonotonic-queue
Nov 5, 2025
[Easy] 485. Max Consecutive Ones
leetcodealgorithmeasycpparrayssliding-windowproblem-solving
leetcodeeasyarraysliding-windowcounting
Nov 5, 2025
[Medium] 18. 4Sum
leetcodealgorithmmediumcpparraystwo-pointerssortingproblem-solving
Oct 29, 2025
Minimal, copy-paste C++ for tree traversals, LCA (binary lifting), segment tree, Fenwick tree, and HLD skeleton.
leetcodetemplatestrees
leetcodetemplatestrees
Oct 29, 2025
Minimal, copy-paste C++ for combinatorics (nCk mod P) and 2D geometry primitives (cross product, point on segment).
leetcodetemplatesmathgeometry
leetcodetemplatesmathgeometry
Oct 29, 2025
Minimal, copy-paste C++ for graph traversal, shortest paths, and topological sort. 0-indexed unless noted.
leetcodetemplatesgraph
leetcodetemplatesgraph
Oct 29, 2025
Minimal, copy-paste C++ for 1D/2D DP, LIS, interval DP, state machine, digit DP, and bitmask DP.
leetcodetemplatesdynamic-programming
leetcodetemplatesdp
Oct 29, 2025
Minimal, copy-paste C++ templates for common structures and patterns. Each snippet is self-contained and uses standard indexing.
leetcodetemplatesdata-structuresalgorithms
leetcodetemplatesdata-structuresalgorithms
Oct 29, 2025
Minimal, copy-paste C++ for sliding window, two pointers, prefix sum, KMP, Manacher, and rolling hash.
leetcodetemplatesarraysstrings
leetcodetemplatesarraysstrings
Oct 29, 2025
Minimal, copy-paste C++ for coordinate compression, meet-in-the-middle, Manacher, Z-algorithm, and bitwise trie (max XOR).
leetcodetemplatesadvanced
leetcodetemplatesadvanced
Oct 29, 2025
LeetCode Categories and Solution Templates
leetcodealgorithmproblem-solvingtemplates
leetcodetemplatespatternsdpgraphsliding-windowtwo-pointersbinary-search
Oct 29, 2025
LC 717: 1-bit and 2-bit Characters
leetcodeeasyarrayparsing
leetcodeeasyarrayparsing
Oct 29, 2025
LC 344: Reverse String
leetcodeeasytwo-pointersstring
leetcodeeasytwo-pointersstring
Oct 28, 2025
LC 708: Insert into a Sorted Circular Linked List
leetcodemediumlinked-listcircular
leetcodemediumlinked-listcircularinsertiontwo-pointers
Oct 28, 2025
LC 636: Exclusive Time of Functions
leetcodemediumstackparsing
leetcodemediumstackparsinglogssimulation
Oct 25, 2025
LC 863: All Nodes Distance K in Binary Tree
leetcodemediumtreedfsbfs
leetcodemediumtreebinary-treedfsbfsgraphrecursion
Oct 22, 2025
LC 1249: Minimum Remove to Make Valid Parentheses
leetcodemediumstringstack
leetcodemediumstringstackparenthesesvalidation
Oct 22, 2025
LC 1094: Car Pooling
leetcodemediumarraysorting
leetcodemediumarraysortingsimulationbucket-sort
Oct 22, 2025
LC 426: Convert Binary Search Tree to Sorted Doubly Linked List
leetcodemediumtreelinked-list
leetcodemediumtreelinked-listbstinorder-traversalrecursion
Oct 22, 2025
LC 348: Design Tic-Tac-Toe
leetcodemediumdesignarray
leetcodemediumdesignarraymatrixoptimization
Oct 22, 2025
LC 419: Battleships in a Board
leetcodemediumarraymatrix
leetcodemediumarraymatrixdfsbattleship
Oct 21, 2025
LC 545: Boundary of Binary Tree
leetcodemediumtreedfs
leetcodemediumtreedfsbinary-treeboundary-traversal
Oct 21, 2025
LC 347: Top K Frequent Elements
leetcodemediumarrayhash-tableheap
leetcodemediumarrayhash-tableheapbucket-sortquickselect
Oct 21, 2025
LC 973: K Closest Points to Origin
leetcodemediumarraysorting
leetcodemediumarraysortingheapquickselect
Oct 21, 2025
LC 1207: Unique Number of Occurrences
leetcodeeasyarrayhash-table
leetcodeeasyarrayhash-tablecounting
Oct 20, 2025
207. Course Schedule
leetcodemediumgraphtopological-sortcycle-detection
Oct 20, 2025
133. Clone Graph
leetcodemediumgraphdfsbfsclone
Oct 20, 2025
752. Open the Lock
leetcodemediumbfsshortest-pathlock
Oct 20, 2025
314. Binary Tree Vertical Order Traversal
leetcodemediumtreebfsvertical-order
Oct 20, 2025
322. Coin Change
leetcodemediumdynamic-programmingdpcoin-change
Oct 20, 2025
47. Permutations II
leetcodealgorithmmediumbacktrackingrecursionduplicates
Oct 20, 2025
77. Combinations
leetcodemediumbacktrackingrecursioncombinations
Oct 20, 2025
46. Permutations
leetcodealgorithmmediumbacktrackingrecursion
Oct 20, 2025
1650. Lowest Common Ancestor of a Binary Tree III
leetcodealgorithmmediumtreebinary-treelca
Oct 20, 2025
2043. Simple Bank System
leetcodealgorithmmediumdesigndata-structure
Oct 20, 2025
1443. Minimum Time to Collect All Apples in a Tree
leetcodealgorithmmediumtreedfsbfsgraph
Oct 20, 2025
84. Largest Rectangle in Histogram
leetcodealgorithmhardstackmonotonic-stack
Oct 20, 2025
695. Max Area of Island
leetcodealgorithmmediumdfsgraphmatrix
Oct 20, 2025
1868. Product of Two Run-Length Encoded Arrays
leetcodealgorithmmediumrun-length-encodingtwo-pointersarray-processing
Oct 20, 2025
[Medium] 1570. Dot Product of Two Sparse Vectors
leetcodealgorithmmediumcpphash-mapdata-structureoptimizationproblem-solving
Oct 20, 2025
[Medium] 1865. Finding Pairs With a Certain Sum
leetcodealgorithmmediumcpphash-mapdata-structureproblem-solving
Oct 20, 2025
[Medium] 437. Path Sum III
leetcodealgorithmmediumcpptreedfsrecursionproblem-solving
Oct 20, 2025
[Medium] 394. Decode String
leetcodealgorithmmediumcppstackstring-processingproblem-solving
Oct 19, 2025
[Medium] 417. Pacific Atlantic Water Flow
leetcodealgorithmmediumcppdfsbfsgraphproblem-solving
Oct 19, 2025
[Medium] 406. Queue Reconstruction by Height
leetcodealgorithmmediumcppgreedysortinglistproblem-solving
Oct 18, 2025
[Medium] 1856. Maximum Sum of Minimum Product
leetcodealgorithmmediumcppstackmonotonic-stackprefix-sumproblem-solving
Oct 18, 2025
[Medium] 316. Remove Duplicate Letters
leetcodealgorithmmediumcppstackmonotonic-stackgreedyproblem-solving
Oct 17, 2025
[Medium] 648. Replace Words
leetcodealgorithmmediumcpptriehash-setstring-processingproblem-solving
Oct 17, 2025
[Medium] 300. Longest Increasing Subsequence
leetcodealgorithmmediumcppdynamic-programmingdpbinary-searchproblem-solving
Oct 17, 2025
[Medium] 503. Next Greater Element II
leetcodealgorithmmediumcppmonotonic-stackstackproblem-solving
Oct 17, 2025
[Medium] 2799. Count Complete Subarrays in an Array
leetcodealgorithmmediumcppsliding-windowhash-mapproblem-solving
Oct 17, 2025
[Medium] 2466. Count Ways To Build Good Strings
leetcodealgorithmmediumcppdynamic-programmingdpproblem-solving
Oct 16, 2025
[Medium] 1124. Longest Well-Performing Interval
leetcodealgorithmmediumcpphash-mapprefix-sumproblem-solving
Oct 15, 2025
[Medium] 494. Target Sum
leetcodealgorithmmediumcppdynamic-programmingdpsubset-sumproblem-solving
Oct 10, 2025
[Medium] 3. Longest Substring Without Repeating Characters
leetcodealgorithmmediumcppsliding-windowhash-mapstringtwo-pointersproblem-solving
Oct 8, 2025
[Medium] 240. Search a 2D Matrix II
leetcodealgorithmmediumcppbinary-searchmatrix2d-arraydivide-conquersearchoptimizationproblem-solving
Oct 6, 2025
[Medium] 912. Sort an Array
leetcodealgorithmmediumcppsortingmerge-sortheap-sortcounting-sortdata-structuresdivide-conquerproblem-solving
Oct 5, 2025
[Hard] 218. The Skyline Problem
leetcodealgorithmhardcppsweep-linepriority-queuedata-structuresunion-findproblem-solving
Oct 4, 2025
[Medium] 990. Satisfiability of Equality Equations
leetcodealgorithmdata-structuresdisjoint-setgraphdfsmediumcppconnected-componentsgraph-coloringproblem-solving
Oct 3, 2025
[Medium] 96. Unique Binary Search Trees
leetcodealgorithmdynamic-programmingdata-structuresmathcatalan-numbersmediumcppbinary-search-treesproblem-solving
Sep 30, 2025
[Medium] 131. Palindrome Partitioning
leetcodealgorithmbacktrackingdata-structuresstringpalindromerecursionmediumcpppartitioningproblem-solving
Sep 29, 2025
[Medium] 77. Combinations
leetcodealgorithmbacktrackingdata-structuresrecursionmediumcppcombinationsdfsproblem-solving
Sep 25, 2025
[Medium] 89. Gray Code
leetcodealgorithmbacktrackingdata-structuresrecursionbit-manipulationmediumcppgray-codeproblem-solving
Sep 25, 2025
[Medium] 54. Spiral Matrix
leetcodealgorithmmatrixdata-structuressimulationtraversalmediumcppspiral-matrixproblem-solving
Sep 25, 2025
[Medium] 50. Pow(x, n)
leetcodealgorithmmathdata-structuresrecursionbit-manipulationmediumcpppowproblem-solving
Sep 24, 2025
[Medium] 62. Unique Paths
leetcodealgorithmdynamic-programmingdata-structuresgridcombinatoricsmediumcppunique-pathsproblem-solving
Sep 24, 2025
[Hard] 25. Reverse Nodes in k-Group
leetcodealgorithmlinked-listrecursivedata-structurespointershardcppreverse-nodesk-grouprecursionproblem-solving
Sep 24, 2025
[Medium] 48. Rotate Image
leetcodealgorithmmatrixdata-structures2d-arraytransformationmediumcpprotate-imagein-placeproblem-solving
Sep 24, 2025
[Medium] 150. Evaluate Reverse Polish Notation
leetcodealgorithmstackdata-structuresmathematical-expressionmediumcppreverse-polish-notationrpnproblem-solving
Sep 24, 2025
[Hard] 317. Shortest Distance from All Buildings
leetcodealgorithmbfsgraphdata-structuresmatrixshortest-pathhardcppshortest-distancebuildingsproblem-solving
Sep 24, 2025
[Medium] 1242. Web Crawler Multithreaded
leetcodealgorithmmultithreadingconcurrencydata-structuressynchronizationmediumcppweb-crawlerconcurrent-programmingproblem-solving
Sep 24, 2025
[Medium] 794. Valid Tic-Tac-Toe State
leetcodealgorithmsimulationdata-structuresgame-logicvalidationmediumcpptic-tac-toegame-validationproblem-solving
Sep 24, 2025
Meta‑Style LeetCode Question List
leetcodealgorithmmetainterview-preparationpractice-listfaangcoding-interviewproblem-solvingcompetitive-programmingdata-structures
Sep 24, 2025
🧩 Hash Table Mastery List
leetcodealgorithmhashdata-structuresinterview-preparationpractice-listhash-tablehash-mapproblem-solvingcompetitive-programming
Sep 24, 2025
LeetCode Linked List Mastery List
leetcodealgorithmlinked-listdata-structuresinterview-preparationpractice-listproblem-solvingcompetitive-programmingpointerstraversal
Sep 24, 2025
[Medium] 24. Swap Nodes in Pairs
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