LeetTracker

LeetCode Problems for Coding Interviews

Browse 325 curated LeetCode problems organized by topic. Includes problems from NeetCode 150, Grind 75, and Blind 75.

325

Total Problems

70

Easy

205

Medium

50

Hard

125

Top 125

150

NeetCode 150

75

Grind 75

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Problems by Topic

Arrays & Hashing

33 problems

EasyTwo Sum
EasyContains Duplicate
EasyValid Anagram
MediumGroup Anagrams
MediumTop K Frequent Elements
MediumProduct of Array Except Self
MediumValid Sudoku
MediumEncode and Decode Strings
MediumLongest Consecutive Sequence
EasyMajority Element
EasyRansom Note
EasyLongest Common Prefix
MediumSubarray Sum Equals K
MediumFind All Anagrams in a String
MediumLargest Number
MediumSort Colors
EasyMove Zeroes
EasySquares of a Sorted Array
MediumInsert Delete GetRandom O(1)
EasyRemove Duplicates from Sorted Array
HardFirst Missing Positive
EasyFind All Numbers Disappeared in Array
EasyMerge Sorted Array
MediumNext Permutation
MediumGame of Life
MediumRotate Array
EasyRemove Element
EasyRange Sum Query - Immutable
MediumRange Sum Query 2D - Immutable
MediumFind the Duplicate Number
MediumFind All Duplicates in an Array
EasyConvert 1D Array Into 2D Array
MediumContiguous Array

Two Pointers

15 problems

EasyValid Palindrome
MediumTwo Sum II - Input Array Is Sorted
Medium3Sum
Medium3Sum Closest
MediumContainer With Most Water
HardTrapping Rain Water
EasyReverse String
EasyValid Palindrome II
Medium3Sum Smaller
MediumSubarray Product Less Than K
Medium4Sum
EasyBackspace String Compare
MediumShortest Unsorted Continuous Subarray
MediumCircular Array Loop
EasyIs Subsequence

Sliding Window

15 problems

EasyBest Time to Buy and Sell Stock
MediumLongest Substring Without Repeating Characters
MediumLongest Repeating Character Replacement
MediumPermutation in String
HardMinimum Window Substring
HardSliding Window Maximum
MediumMinimum Size Subarray Sum
MediumLongest Substring with At Most K Distinct Characters
MediumFruit Into Baskets
MediumMax Consecutive Ones III
HardSubstring with Concatenation of All Words
HardSliding Window Median
HardMinimum Number of K Consecutive Bit Flips
HardCount Unique Characters of All Substrings of a Given String
EasyMaximum Average Subarray I

Stack

16 problems

EasyValid Parentheses
MediumMin Stack
MediumEvaluate Reverse Polish Notation
MediumDaily Temperatures
MediumCar Fleet
HardLargest Rectangle in Histogram
EasyImplement Queue using Stacks
MediumAsteroid Collision
MediumBasic Calculator II
MediumDecode String
EasyNext Greater Element I
MediumNext Greater Element II
MediumRemove K Digits
MediumOnline Stock Span
HardBasic Calculator
HardLongest Valid Parentheses

Binary Search

16 problems

EasyBinary Search
MediumSearch a 2D Matrix
MediumKoko Eating Bananas
MediumFind Minimum in Rotated Sorted Array
MediumSearch in Rotated Sorted Array
MediumTime Based Key-Value Store
HardMedian of Two Sorted Arrays
EasyFirst Bad Version
MediumFind K Closest Elements
MediumSearch a 2D Matrix II
MediumFind Peak Element
MediumFind First and Last Position of Element in Sorted Array
MediumCapacity To Ship Packages Within D Days
MediumPeak Index in a Mountain Array
MediumSearch in Rotated Sorted Array II
HardCount of Range Sum

Linked List

22 problems

EasyReverse Linked List
EasyMerge Two Sorted Lists
EasyLinked List Cycle
MediumReorder List
MediumRemove Nth Node From End of List
MediumCopy List with Random Pointer
MediumAdd Two Numbers
MediumLRU Cache
HardMerge K Sorted Lists
HardReverse Nodes in k-Group
EasyMiddle of the Linked List
MediumLinked List Cycle II
MediumSwap Nodes in Pairs
MediumSort List
EasyPalindrome Linked List
EasyIntersection of Two Linked Lists
EasyRemove Duplicates from Sorted List
MediumRotate List
MediumFlatten a Multilevel Doubly Linked List
EasyRemove Linked List Elements
MediumReverse Linked List II
MediumOdd Even Linked List

Trees

37 problems

EasyInvert Binary Tree
EasyMaximum Depth of Binary Tree
EasyDiameter of Binary Tree
EasyBalanced Binary Tree
EasySame Tree
EasySubtree of Another Tree
MediumLowest Common Ancestor of a Binary Search Tree
MediumBinary Tree Level Order Traversal
MediumBinary Tree Right Side View
MediumCount Good Nodes in Binary Tree
MediumValidate Binary Search Tree
MediumKth Smallest Element in a BST
MediumConstruct Binary Tree from Preorder and Inorder Traversal
HardBinary Tree Maximum Path Sum
HardSerialize and Deserialize Binary Tree
MediumLowest Common Ancestor of a Binary Tree
MediumBinary Tree Zigzag Level Order Traversal
MediumPath Sum II
MediumPath Sum III
MediumMaximum Width of Binary Tree
MediumInsert into a Binary Search Tree
MediumBinary Search Tree Iterator
EasySymmetric Tree
EasyConvert Sorted Array to Binary Search Tree
EasyBinary Tree Inorder Traversal
MediumDelete Node in a BST
MediumSum Root to Leaf Numbers
MediumPopulating Next Right Pointers in Each Node
HardBinary Tree Cameras
EasyMerge Two Binary Trees
MediumMaximum Binary Tree
MediumAll Nodes Distance K in Binary Tree
MediumBinary Tree Level Order Traversal II
EasyAverage of Levels in Binary Tree
EasyPath Sum
EasyMinimum Depth of Binary Tree
EasyBinary Tree Paths

Tries

11 problems

MediumImplement Trie (Prefix Tree)
MediumDesign Add and Search Words Data Structure
HardWord Search II
EasyIndex Pairs of a String
HardDesign Search Autocomplete System
HardWord Squares
MediumLongest Word in Dictionary
MediumMaximum XOR of Two Numbers in an Array
HardConcatenated Words
HardPrefix and Suffix Search
HardPalindrome Pairs

Heap

18 problems

EasyKth Largest Element in a Stream
EasyLast Stone Weight
MediumK Closest Points to Origin
MediumKth Largest Element in an Array
MediumTask Scheduler
MediumDesign Twitter
HardFind Median from Data Stream
MediumTop K Frequent Words
HardIPO
MediumKth Smallest Element in a Sorted Matrix
HardSmallest Range Covering Elements from K Lists
MediumFind K Pairs with Smallest Sums
HardRearrange String k Distance Apart
HardCourse Schedule III
HardMaximum Frequency Stack
MediumSort Characters By Frequency
MediumReorganize String
HardEmployee Free Time

Backtracking

19 problems

MediumGenerate Parentheses
MediumSubsets
MediumCombination Sum
MediumPermutations
MediumSubsets II
MediumCombination Sum II
MediumWord Search
MediumPalindrome Partitioning
MediumLetter Combinations of a Phone Number
HardN-Queens
MediumCombination Sum IV
MediumLetter Case Permutation
MediumPermutations II
MediumCombinations
MediumCombination Sum III
HardSudoku Solver
MediumGeneralized Abbreviation
MediumFactor Combinations
MediumSplit a String Into the Max Number of Unique Substrings

Graphs

32 problems

MediumNumber of Islands
MediumClone Graph
MediumMax Area of Island
MediumPacific Atlantic Water Flow
MediumSurrounded Regions
MediumRotting Oranges
MediumWalls and Gates
MediumCourse Schedule
MediumCourse Schedule II
MediumRedundant Connection
MediumNumber of Connected Components in an Undirected Graph
MediumGraph Valid Tree
HardWord Ladder
EasyFlood Fill
Medium01 Matrix
MediumAccounts Merge
MediumMinimum Height Trees
HardReconstruct Itinerary
MediumMin Cost to Connect All Points
MediumNetwork Delay Time
HardSwim in Rising Water
HardAlien Dictionary
MediumCheapest Flights Within K Stops
MediumMinimum Knight Moves
MediumIs Graph Bipartite?
MediumAll Paths From Source to Target
MediumShortest Path in Binary Matrix
EasyFind if Path Exists in Graph
MediumEvaluate Division
MediumSnakes and Ladders
MediumSequence Reconstruction
HardSort Items by Groups Respecting Dependencies

Dynamic Programming

45 problems

MediumBest Time to Buy and Sell Stock II
HardBest Time to Buy and Sell Stock III
HardBest Time to Buy and Sell Stock IV
MediumBest Time to Buy and Sell Stock with Transaction Fee
EasyClimbing Stairs
EasyMin Cost Climbing Stairs
MediumHouse Robber
MediumHouse Robber II
MediumLongest Palindromic Substring
MediumPalindromic Substrings
MediumDecode Ways
MediumCoin Change
MediumMaximum Product Subarray
MediumWord Break
MediumLongest Increasing Subsequence
MediumPartition Equal Subset Sum
EasyLongest Palindrome
MediumMaximum Subarray
MediumPerfect Squares
MediumUnique Paths
MediumUnique Paths II
MediumLongest Common Subsequence
MediumBest Time to Buy and Sell Stock with Cooldown
MediumCoin Change II
MediumTarget Sum
MediumInterleaving String
HardLongest Increasing Path in a Matrix
HardDistinct Subsequences
MediumEdit Distance
HardBurst Balloons
HardRegular Expression Matching
MediumMinimum Path Sum
MediumMaximal Square
MediumDelete and Earn
MediumNumber of Longest Increasing Subsequence
MediumArithmetic Slices
MediumOnes and Zeroes
HardWildcard Matching
MediumStone Game
HardDungeon Game
MediumUgly Number II
MediumPartition to K Equal Sum Subsets
HardMaximum Profit in Job Scheduling
HardWord Break II
MediumLongest Palindromic Subsequence

Greedy

10 problems

MediumJump Game
MediumJump Game II
MediumGas Station
MediumHand of Straights
MediumMerge Triplets to Form Target Triplet
MediumPartition Labels
MediumValid Parenthesis String
MediumMaximum Length of Pair Chain
MediumQueue Reconstruction by Height
MediumMinimum Number of Arrows to Burst Balloons

Intervals

7 problems

MediumInsert Interval
MediumMerge Intervals
MediumNon-overlapping Intervals
EasyMeeting Rooms
MediumMeeting Rooms II
HardMinimum Interval to Include Each Query
MediumInterval List Intersections

Math & Geometry

14 problems

MediumRotate Image
MediumSpiral Matrix
MediumSpiral Matrix II
MediumSet Matrix Zeroes
EasyHappy Number
EasyPlus One
MediumPow(x, n)
MediumMultiply Strings
MediumDetect Squares
EasyAdd Binary
MediumRandom Pick with Weight
MediumString to Integer (atoi)
EasyRoman to Integer
EasyPalindrome Number

Bit Manipulation

9 problems

EasySingle Number
EasyNumber of 1 Bits
EasyCounting Bits
EasyReverse Bits
EasyMissing Number
MediumSum of Two Integers
MediumReverse Integer
MediumSingle Number II
EasyPower of Two

Design

6 problems

EasyMoving Average from Data Stream
MediumDesign Hit Counter
HardLFU Cache
MediumDesign Circular Queue
MediumFlatten Nested List Iterator
EasyDesign HashMap

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