LeetCode

1-100

No.	Title	Tag	Solution	Difficulty	UnitTest	Post
0001	Two Sum	Array, Dictionary	TwoSum	Easy	💡	📄
0002	Add Two Numbers	Linked List, Recursion	AddTwoNumbers	Medium	💡
0003	Longest Substring Without Repeating Characters	String	LengthOfLongestSubstring	Medium	💡
0004		Array		Hard
0005	Longest Palindromic Substring	String	LongestPalindrome	Medium	💡
0006
0007	Reverse Integer	Array.Reverse, string.Contains, string.Replace	Reverse	Easy	💡
0008
0009	Palindrome Number	%,/	IsPalindrome	Easy	💡	📄
0010
0011	Container With Most Water	Array, Two Pointers, Greedy		Medium	💡
0012
0013	Roman to Integer	Dictionary	RomanToInt	Easy	💡	📄
0014	Longest Common Prefix	Array	LongestCommonPrefix	Easy	💡	📄
0015	3Sum	Array	ThreeSum	Medium	💡
0016	3Sum Closest	Array	ThreeSumClosest	Medium	💡
0017
0018	4Sum	Array, HashSet, Binary Search	FourSum	Medium	💡
0019	Remove Nth Node From End of List	Linked List	RemoveNthFromEnd	Medium	💡
0020	Valid Parentheses	Stack	IsValid	Easy	💡	📄
0021	Merge Two Sorted Lists	Linked List	MergeTwoLists	Easy	💡	📄
0022
0023
0024	Swap Nodes in Pairs	Linked List	SwapPairs	Medium	💡
0025	Reverse Nodes in k-Group	Linked List	ReverseKGroup	Hard	💡
0026	Remove Duplicates from Sorted Array	Array	RemoveDuplicates	Easy	💡	📄
0027	Remove Element	Array	RemoveElement	Easy	💡	📄
0028	Implement strStr()	string.Contains	StrStr	Easy	💡
0029
0030
0031		Array		Medium
0032	Longest Valid Parentheses	Stack	LongestValidParentheses	Hard	💡
0033		Array		Medium
0034		Array		Medium
0035	Search Insert Position	Binary Search, Array	SearchInsert	Easy	💡	📄
0036	Valid Sudoku	Hash Set, Array	ValidSudoku	Medium	💡
0037	Sudoku Solver	Array, Backtracking	SolveSuduku	Hard	💡
0038
0039		Array		Medium
0040		Array, Backtracking		Medium
0041		Array		Hard
0042		Array		Hard
0043	Multiply Strings	String	Multiply	Medium	💡
0044
0045	Jump Game II	Array, DP, Greedy		Medium	💡
0046	Permutations	Array, Backtracking	Permute	Medium	💡
0047		Array		Medium
0048	Rotate Image	Array, Matrix	Rotate	Medium
0049	Group Anagrams	String	GroupAnagrams	Medium	💡
0050
0051		Array		Hard
0052
0053	Maximum Subarray	Array	MaxSubArray	Easy	💡
0054		Array		Medium
0055		Array		Medium
0056	Merge Intervals	Array	Merge	Medium	💡
0057		Array		Medium
0058	Length of Last Word	String	LengthOfLastWord	Easy	💡	📄
0059	Spiral Matrix II	Array, Matrix	GenerateMatrix	Medium	💡
0060
0061
0062
0063		Array		Medium
0064		Array		Medium
0065
0066	Plus One	Array	PlusOne	Easy	💡	📄
0067	Add Binary	Bit Manipulation	AddBinary	Easy	💡	📄
0068		Array		Hard
0069	Sqrt(x)	Enumeration	MySqrt	Easy	💡
0070	Climbing Stairs	Fibonacci, DP	ClimbStairs	Easy	💡
0071
0072
0073		Array		Medium
0074	Search a 2D Matrix	Array	SearchMatrix	Medium	💡
0075	Sort Colors	Array, Sorting	SortColors	Medium
0076
0077	Combinations	Backtracking	Combine	Medium	💡
0078		Array		Medium
0079		Array		Medium
0080		Array		Medium
0081		Array		Medium
0082	Remove Duplicates from Sorted List II	Linked List	DeleteDuplicates	Medium	💡
0083	Remove Duplicates from Sorted List	Linked List	DeleteDuplicates	Easy	💡	📄
0084		Array		Hard
0085		Array		Hard
0086
0087
0088	Merge Sorted Array	Array	Merge	Easy
0089
0090		Array		Medium
0091
0092
0093
0094	Binary Tree Inorder Traversal	Tree, DFS, Binary Tree	InorderTraversal	Easy	❌	📄
0095
0096
0097
0098
0099
0100	Same Tree	Tree, DFS, BFS, Binary Tree	IsSameTree	Easy	❌	📄

101-200

No.	Title	Tag	Solution	Difficulty	UnitTest
0101	Symmetric Tree	Tree, DFS, BFS, Binary Tree	IsSymmetric	Easy	❌
0102	Binary Tree Level Order Traversal	Tree, BFS, Binary Tree	LevelOrder	Medium
0103
0104	Maximum Depth of Binary Tree	Tree, DFS, BFS, Binary Tree	MaxDepth	Easy
0105	Construct Binary Tree from Preorder and Inorder Traversal	Array, Tree, Binary Tree	BuildTree	Medium
0106
0107
0108	Convert Sorted Array to Binary Search Tree	Array, Tree	SortedArrayToBST	Easy
0109
0110
0111	Minimum Depth of Binary Tree	Tree, DFS, BFS, Binary Tree	MinDepth	Easy
0112
0113	Path Sum II	Tree, DFS, Binary Tree	PathSum	Medium
0114	Flatten Binary Tree to Linked List	Tree, DFS, Binary Tree	Flatten	Medium
0115
0116	Populating Next Right Pointers in Each Node	Linked List, Tree, DFS, BFS, Binary Tree	Connect	Medium
0117
0118	Pascal's Triangle	Array, DP	Generate	Easy	💡
0119	Pascal's Triangle II	Array, DP	GetRow	Easy	💡
0120	Triangle	Array, DP	MinimumTotal	Medium	💡
0121	Best Time to Buy and Sell Stock	DP	MaxProfit	Easy	💡
0122
0123
0124
0125	Valid Palindrome	Binary Search	IsPalindrome	Easy	💡
0126
0127
0128
0129
0130
0131
0132
0133
0134
0135
0136	Single Number	Array, Bit Manipulation, XOR	SingleNumber	Easy	💡
0137
0138
0139
0140
0141	Linked List Cycle	Linked List, Two Pointers	HasCycle	Easy	❌
0142	Linked List Cycle II	Linked List, HastSet	DetectCycle	Medium
0143	Reorder List	Linked List	ReorderList	Medium
0144	Binary Tree Preorder Traversal	Tree, DFS, Binary Tree	PreorderTraversal	Easy
0145	Binary Tree Postorder Traversal	Tree, DFS, Binary Tree	PostorderTraversal	Easy
0146
0147
0148
0149
0150
0151
0152
0153
0154
0155	Min Stack	Stack	MinStack	Easy
0156
0157
0158
0159
0160	Intersection of Two Linked Lists	Linked List, Two Pointers	GetIntersectionNode	Easy
0161
0162	Find Peak Element	Array	FindPeakElement	Medium	💡
0163
0164
0165
0166
0167	Two Sum II - Input array is sorted	Array, Binary Search	TwoSum	Medium	💡
0168	Excel Sheet Column Title	Array, char	ConvertToTitle	Easy	💡
0169	Majority Element	Array, Dictionary	MajorityElement	Easy	💡
0170
0171
0172	Factorial Trailing Zeroes	Enumeration	TrailingZeroes	Easy	💡
0173	Binary Search Tree Iterator	Stack, Tree	BSTIterator	Medium
0174
0175
0176
0177
0178
0179
0180
0181
0182
0183
0184
0185
0186
0187	Repeated DNA Sequences	String, Hash Table	FindRepeatedDnaSequences	Medium	💡
0188
0189	Rotate Array	Array	Rotate	Medium
0190	Reverse Bits	Bit Manipulation	reverseBits	Easy
0191	Number of 1 Bits	Bit Manipulation	HammingWeight	Easy
0192
0193
0194
0195
0196
0197
0198	House Robber	Array, DP	Rob	Medium	💡
0199	Binary Tree Right Side View	Tree, DFS, BFS, Binary Tree	RightSideView	Medium
0200

201-300

No.	Title	Tag	Solution	Difficulty	UnitTest
0202	Happy Number	HashSet	IsHappy	Easy	💡
0203	Remove Linked List Elements	Linked List	RemoveElements	Easy	💡
0204	Count Primes	Array	CountPrimes	Easy	💡
0205	Isomorphic Strings	Dictionary	IsIsomorphic	Easy	💡
0206	Reverse Linked List	Linked List, Recursion	ReverseList	Easy	💡
0215	Kth Largest Element in an Array	Array	FindKthLargest	Medium	💡
0217	Contains Duplicate	HashSet	ContainsDuplicate	Easy	💡
0219	Contains Duplicate II	Dictionary	ContainsNearbyDuplicate	Easy	💡
0225	Implement Stack using Queues	Stack	MyStack	Easy
0226	Contains Duplicate II	Tree, DFS, BFS, Binary Tree	InvertTree	Easy
0215	Kth Largest Element in an Array	Array	FindKthLargest	Medium	💡
0230	Kth Smallest Element in a BST	Tree, DFS, BFS, Binary Tree	KthSmallest	Medium
0231	Power of Two	Bit Manipulation, Shift	IsPowerOfTwo	Easy	💡
0232	Contains Duplicate II	Queue, Stack	MyQueue	Easy
0234	Palindrome Linked List	Stack, Linked List	IsPalindrome	Easy	💡
0236	Lowest Common Ancestor of a Binary Tree	Tree, DFS, Binary Tree	LowestCommonAncestor	Medium
0235	Lowest Common Ancestor of a Binary Search Tree	Tree, DFS, BFS, Binary Tree	LowestCommonAncestor	Easy
0237	Delete Node in a Linked List	Linked List	DeleteNode	Easy
0238	Product of Array Except Self	Array	ProductExceptSelf	Medium	💡
0240	Search a 2D Matrix II	Array	SearchMatrix	Medium	💡
0242	Valid Anagram	Array	IsAnagram	Easy	💡
0257	Binary Tree Paths	Tree, DFS, Binary Tree	BinaryTreePaths	Easy
0258	Add Digits	Remainder(%) Operator	AddDigits	Easy	💡
0268	Missing Number	Array, Binary Search, Bit Manipulation, Bit Manipulation	MissingNumber	Easy	💡
0278	First Bad Version	Binary Search	FirstBadVersion	Easy	❌
0283	Move Zeroes	Enumeration	MoveZeroes	Easy
0290	Word Pattern	String	WordPattern	Easy	💡
0297	Serialize and Deserialize Binary Tree	String, Tree	Codec	Hard

301-400

No.	Title	Tag	Solution	Difficulty	UnitTest
0326	Power of Three	Remainder(%) Operator	IsPowerOfThree	Easy	💡
0334	Increasing Triplet Subsequence	Array	IncreasingTriplet	Medium	💡
0338		Bit Manipulation, DP		Easy
0342		Bit Manipulation, Recursion		Easy
0344	Reverse String	String	ReverseString	Easy
0347	Top K Frequent Elements	Array	TopKFrequent	Medium	💡
0350
0378	Kth Smallest Element in a Sorted Matrix	Binary Search, Matrix	KthSmallest	Medium	💡
0383
0387	First Unique Character in a String	Dictionary	FirstUniqChar	Easy	💡
0389	Find the Difference	Bit Manipulation, XOR	FindTheDifference	Easy	💡
0392	Is Subsequence	Two Pointers, DP	IsSubsequence	Easy	💡

401-500

No.	Title	Tag	Solution	Difficulty	UnitTest
0401		Bit Manipulation		Easy
0404	Sum of Left Leaves	Tree, DFS, BFS, Binary Tree	SumOfLeftLeaves	Easy
0405		Bit Manipulation		Easy
0409	Longest Palindrome	String, Stack, Dictionary	LongestPalindrome	Easy	💡
0415	Add Strings		AddStrings	Easy	💡
0450	Delete Node in a BST	Tree, BST, Binary Tree	DeleteNode	Medium
0451	Sort Characters By Frequency	String, Dictionary	FrequencySort	Medium	💡
0461		Bit Manipulation		Easy
0476	Number Complement	Bit Manipulation	FindComplement	Easy	💡
0485	Max Consecutive Ones		FindMaxConsecutiveOnes	Easy	💡
0500

501-600

No.	Title	Tag	Solution	Difficulty	UnitTest
0509	Fibonacci Number	Fibonacci, Recursion, DP	Fib	Easy	💡
0542	01 Matrix	Array, DP, BFS, Matrix	UpdateMatrix	Medium	💡
0557	Reverse Words in a String III	Array, String	ReverseWords	Easy	💡
0560	Subarray Sum Equals K	Array, Dictionary	SubarraySum	Medium	💡
0566	Reshape the Matrix	Array, Matrix	MatrixReshape	Medium	💡
0567	Permutation in String	String	CheckInclusion	Medium	💡
0589	N-ary Tree Preorder Traversal	Tree	Preorder	Easy

601-700

No.	Title	Tag	Solution	Difficulty	UnitTest
0611	Valid Triangle Number	Binary Search	TriangleNumber	Medium	💡
0617	Merge Two Binary Trees	Tree, DFS, BFS, Binary Tree	MergeTrees	Easy
0645		Array, Bit Manipulation		Easy
0653	Two Sum IV - Input is a BST	Tree, DFS, BFS, Binary Tree	FindTarget	Easy
0682	Baseball Game	Stack	CalPoints	Easy	💡
0695	Max Area of Island	Array, DFS, BFS, Matrix	MaxAreaOfIsland	Medium	💡
0693		Bit Manipulation		Easy
0700	Search in a Binary Search Tree	Tree, Binary Tree	SearchBST	Easy

701-800

No.	Title	Tag	Solution	Difficulty	UnitTest
0701	Insert into a Binary Search Tree	Tree, BST, Binary Tree	InsertIntoBST	Medium
0704	Binary Search	Array, Binary Tree	Search	Easy	💡
0705		Array, Linked List		Easy
0706	Design HashMap	Array, Hash Table, Linked List	MyHashMap	Easy
0707	Design Linked List	Linked List	MyLinkedList	Medium
0709	To Lower Case	Char	ToLowerCase	Easy	💡
0717	1-bit and 2-bit Characters	Array	IsOneBitCharacter	Easy	💡
0718	Maximum Length of Repeated Subarray	Array, Matrix	FindLength	Medium	💡
0728	Self Dividing Numbers	Remainder(%) operator	SelfDividingNumbers	Easy	💡
0733	Flood Fill	Array, DFS, BFS, Matrix	FloodFill	Easy	💡
0746		Array, DP		Easy
0762		Bit Manipulation		Easy
0771	Jewels and Stones	string.Contains	NumJewelsInStones	Easy	💡
0784	Letter Case Permutation	String, Backtracking, BitManipulation	LetterCasePermutation	Medium	💡
0791	Custom Sort String	Dictionary, Hash Table	❓ CustomSortString	Medium	💡

801-900

No.	Title	Tag	Solution	Difficulty	UnitTest
0824	Goat Latin	DP	ToGoatLatin	Easy	💡
0841	Keys and Rooms	DFS, BFS, Graph	CanVisitAllRooms	Medium	💡
0852	Peak Index in a Mountain Array	Array	PeakIndexInMountainArray	Easy	💡
0868		Bit Manipulation		Easy
0876	Middle of the Linked List	Linked List	MiddleNode	Easy	💡
0897	Increasing Order Search Tree	Tree, DFS, BFS, Binary Tree	IncreasingBST	Easy

901-1000

No.	Title	Tag	Solution	Difficulty	UnitTest
0905	Sort Array By Parity	Array	SortArrayByParity	Easy	💡
0912	Sort an Array	Quick Sort	SortArray	Medium	💡
0917	Reverse Only Letters	String	ReverseOnlyLetters	Easy	💡
0938	Range Sum of BST	Tree, DFS, BFS, Binary Tree	RangeSumBST	Easy	💡
0961	N-Repeated Element in Size 2N Array	Array	RepeatedNTimes	Easy	💡
0977	Squares of a Sorted Array	Quick Sort	SortedSquares	Easy	💡
0994	Rotting Oranges	Array, BFS, Matrix	OrangesRotting	Medium	💡
0997	Find the Town Judge	Array	FindJudge	Easy	💡

1001-1100

No.	Title	Tag	Solution	Difficulty	UnitTest
1022	Sum of Root To Leaf Binary Numbers	Tree	SumRootToLeaf	Easy
1025		DP		Easy
1047	Remove All Adjacent Duplicates In String	String	RemoveDuplicates	Easy	💡

1101-1200

No.	Title	Tag	Solution	Difficulty	UnitTest
1009		Bit Manipulation		Easy
1108	Defanging an IP Address	String	DefangIPaddr	Easy	💡
1137		DP		Easy

1201-1300

No.	Title	Tag	Solution	Difficulty	UnitTest
1207	Unique Number of Occurrences	Array	UniqueOccurrences	Easy	💡
1220	Count Vowels Permutation	DP	CountVowelPermutation	Hard	💡
1221	Split a String in Balanced Strings	String	BalancedStringSplit	Easy	💡
1249	Minimum Remove to Make Valid Parentheses	String	MinRemoveToMakeValid	Medium	💡
1281	Subtract the Product and Sum of Digits of an Integer	Enumeration, Remainder(%) operator	SubtractProductAndSum	Easy	💡
1290	Convert Binary Number in a Linked List to Integer	Linked List	GetDecimalValue	Easy	💡
1295	Find Numbers with Even Number of Digits	Array	FindNumbers	Easy	💡
1299	Replace Elements with Greatest Element on Right Side	Array	ReplaceElements	Easy	💡

1301-

No.	Title	Tag	Solution	Difficulty	UnitTest
1313	Decompress Run-Length Encoded List	List, Array	DecompressRLElist	Easy	💡
1342	Nnumber of Steps to Reduce a Number to Zero	Bit Manipulation	NumberOfSteps	Easy	💡
1351	Count Negative Numbers in a Sorted Matrix	Array	CountNegatives	Easy	💡
1356		Array, Bit Manipulation		Easy
1365	How Many Numbers Are Smaller Than the Current Number	Array	SmallerNumbersThanCurrent	Easy	💡
1370	Increasing Decreasing String	String, Char	SortString	Easy	💡
1380	Lucky Numbers in a Matrix	Array, List	LuckyNumbers	Easy	💡
1389	Create Target Array in the Given Order	Array, List	CreateTargetArray	Easy	💡
1431	Kids With the Greatest Number of Candies	Array, List	KidsWithCandies	Easy	💡
1436	Destination City	Enumeration	DestCity	Easy	💡
1460	Make Two Arrays Equal by Reversing Sub-arrays	Array	CanBeEqual	Easy	💡
1470	Shuffle the Array	Array	Shuffle	Easy	💡
1480	Running Sum of 1d Array	Array	RunningSum	Easy	💡
1486	XOR Operation in an Array	Bit Manipulation, XOR	XorOperation	Easy	💡
1491	Number of Good Pairs	Array	Average	Easy	💡
1512	Number of Good Pairs	Array	NumIdenticalPairs	Easy	💡
1523	Count Odd Numbers in an Interval Range	/,%	CountOdds	Easy	💡
1528	Shuffle String	Array	RestoreString	Easy	💡
1534	Count Good Triplets	Array	CountGoodTriplets	Easy	💡
1557	Minimum Number of Vertices to Reach All Nodes	Graph	FindSmallestSetOfVertices	Medium	💡
1588	Sum of All Odd Length Subarrays	Array	SumOddLengthSubarrays	Easy	💡
1603	Design Parking System	Array	ParkingSystem	Easy	💡
1614	Maximum Nesting Depth of the Parentheses	String	MaxDepth	Easy	💡
1636	Sort Array by Increasing Frequency	Array	FrequencySort	Easy	💡
1646		Array, DP		Easy
1662	Check If Two String Arrays are Equivalent	Array	ArrayStringsAreEqual	Easy	💡
1672	Richest Customer Wealth	Array	MaximumWealth	Easy	💡
1678	Goal Parser Interpretation	Array	Interpret	Easy	💡
1684	Count the Number of Consistent Strings	Array, Bit Manipulation	CountConsistentStrings	Easy	💡
1688	Count of Matches in Tournament	Enumeration, Remainder(%) operator	NumberOfMatches	Easy	💡
1700	Number of Students Unable to Eat Lunch	Queue, Array	CountStudents	Easy	💡
1716	Calculate Money in Leetcode Bank	Math, Trapezoid formula	TotalMoney	Easy	💡
1720	Decode XORed Array	Array, Bit Manipulation, XOR	Decode	Easy	💡
1748	Sum of Unique Elements	Dictionary, Array	SumOfUnique	Easy	💡
1763		Divide and Conquer, Bit Manipulation		Easy
1768	Merge Strings Alternately	String	MergeAlternately	Easy	💡
1773	Count Items Matching a Rule	List, Array	CountMatches	Easy	💡
1784	Check if Binary String Has at Most One Segment of Ones	string.IndexOf	CheckOnesSegment	Easy	💡
1790	Check if One String Swap Can Make Strings Equal	char	AreAlmostEqual	Easy	💡
1796	Second Largest Digit in a String	HashSet	SecondHighest	Easy	💡
1800	Maximum Ascending Subarray Sum	Array	MaxAscendingSum	Easy	💡
1805	Number of Different Integers in a String	String	NumDifferentIntegers	Easy	💡
1816	Truncate Sentence	Array	TruncateSentence	Easy	💡
1822	Sign of the Product of an Array	Array	ArraySign	Easy	💡
1823	Find the Winner of the Circular Game	Array	FindTheWinner	Medium	💡
1827	Minimum Operations to Make the Array Increasing	Array	MinOperations	Easy	💡
1832	Check if the Sentence Is Pangram	Dictionary	CheckIfPangram	Easy	💡
1837	Sum of Digits in Base K	Remainder operator	SumBase	Easy	💡
1839	Longest Substring Of All Vowels in Order	List	LongestBeautifulSubstring	Medium	💡
1844	Replace All Digits with Characters	Char, Array	ReplaceDigits	Easy	💡
1848	Minimum Distance to the Target Element	Array	GetMinDistance	Easy	💡
1859
1869
1863		Array, Bit Manipulation		Easy
1876
1880
1881

2001-

No.	Title	Tag	Solution	Difficulty	UnitTest
2001		Array		Medium
2006	Count Number of Pairs With Absolute Difference K	Array	CountKDifference	Easy	💡
2095	Delete the Middle Node of a Linked List	Linked List	DeleteMiddle	Medium	💡
2206		Array, Bit Manipulation		Easy
2220		Bit Manipulation		Easy
2239
2248