LeetCode Solutions

Getting Started

In this repository, I'll work on solutions to LeetCode problems.

All codes are formatted by clang-format and prettier.

Problem Sets

#	Title	Solution	Difficulty
0001	Two Sum	C++, Python	Easy
0002	Add Two Numbers	C++, Python	Medium
0003	Longest Substring Without Repeating Characters	C++, Python	Medium
0004	Median of Two Sorted Arrays	C++, Python	Hard
0005	Longest Palindromic Substring	C++, Python	Medium
0006	ZigZag Conversion	C++, Python	Medium
0007	Reverse Integer	C++, Python	Easy
0008	String to Integer (atoi)	C++, Python	Medium
0009	Palindrome Number	C++, Python	Easy
0010	Regular Expression Matching	C++, Python	Hard
0011	Container With Most Water	C++, Python	Medium
0012	Integer to Roman	C++, Python	Medium
0013	Roman to Integer	C++, Python	Easy
0014	Longest Common Prefix	C++, Python	Easy
0015	3Sum	C++, Python	Medium
0016	3Sum Closest	C++, Python	Medium
0017	Letter Combinations of a Phone Number	C++, Python	Medium
0018	4Sum	C++, Python	Medium
0019	Remove Nth Node From End of List	C++, Python	Medium
0020	Valid Parentheses	C++, Python	Easy
0021	Merge Two Sorted Lists	C++, Python	Easy
0022	Generate Parentheses	C++, Python	Medium
0023	Merge k Sorted Lists	C++, Python	Hard
0024	Swap Nodes in Pairs	C++, Python	Medium
0025	Reverse Nodes in k-Group	C++, Python	Hard
0026	Remove Duplicates from Sorted Array	C++, Python	Easy
0027	Remove Element	C++, Python	Easy
0028	Implement strStr()	C++, Python	Easy
0029	Divide Two Integers	C++, Python	Medium
0030	Substring with Concatenation of All Words	C++, Python	Hard
0031	Next Permutation	C++, Python	Medium
0032	Longest Valid Parentheses	C++, Python	Hard
0033	Search in Rotated Sorted Array	C++, Python	Medium
0034	Find First and Last Position of Element in Sorted Array	C++, Python	Medium
0035	Search Insert Position	C++, Python	Easy
0036	Valid Sudoku	Python	Medium
0037	Sudoku Solver	C++, Python	Hard
0038	Count and Say	C++, Python	Easy
0039	Combination Sum	C++, Python	Medium
0040	Combination Sum II	C++, Python	Medium
0041	First Missing Positive	C++, Python	Hard
0042	Trapping Rain Water	C++, Python	Hard
0043	Multiply Strings	Python	Medium
0044	Wildcard Matching	C++, Python	Hard
0045	Jump Game II	C++, Python	Hard
0046	Permutations	C++, Python	Medium
0047	Permutations II	C++, Python	Medium
0048	Rotate Image	C++, Python	Medium
0049	Group Anagrams	C++, Python	Medium
0050	Pow(x, n)	C++, Python	Medium
0051	N-Queens	C++, Python	Hard
0052	N-Queens II	C++, Python	Hard
0053	Maximum Subarray	C++, Python	Easy
0054	Spiral Matrix	C++, Python	Medium
0055	Jump Game	C++, Python	Medium
0056	Merge Intervals	C++, Python	Medium
0057	Insert Interval	C++, Python	Hard
0058	Length of Last Word	C++, Python	Easy
0059	Spiral Matrix II	C++, Python	Medium
0060	Permutation Sequence	C++, Python	Medium
0061	Rotate List	C++, Python	Medium
0062	Unique Paths	C++, Python	Medium
0063	Unique Paths II	C++, Python	Medium
0064	Minimum Path Sum	C++, Python	Medium
0065	Valid Number	Python	Hard
0066	Plus One	C++, Python	Easy
0067	Add Binary	C++, Python	Easy
0068	Text Justification	C++, Python	Hard
0069	Sqrt(x)	C++, Python	Easy
0070	Climbing Stairs	C++, Python	Easy
0071	Simplify Path	C++, Python	Medium
0072	Edit Distance	C++, Python	Hard
0073	Set Matrix Zeroes	C++, Python	Medium
0074	Search a 2D Matrix	C++, Python	Medium
0075	Sort Colors	C++, Python	Medium
0076	Minimum Window Substring	C++, Python	Hard
0077	Combinations	C++, Python	Medium
0078	Subsets	C++, Python	Medium
0079	Word Search	C++, Python	Medium
0080	Remove Duplicates from Sorted Array II	C++, Python	Medium
0081	Search in Rotated Sorted Array II	C++, Python	Medium
0082	Remove Duplicates from Sorted List II	C++, Python	Medium
0083	Remove Duplicates from Sorted List	C++, Python	Easy
0084	Largest Rectangle in Histogram	C++, Python	Hard
0085	Maximal Rectangle		Hard
0086	Partition List	C++, Python	Medium
0087	Scramble String		Hard
0088	Merge Sorted Array	C++, Python	Easy
0089	Gray Code	C++, Python	Medium
0090	Subsets II	C++, Python	Medium
0091	Decode Ways	C++, Python	Medium
0092	Reverse Linked List II	C++, Python	Medium
0093	Restore IP Addresses	C++, Python	Medium
0094	Binary Tree Inorder Traversal	C++, Python	Medium
0095	Unique Binary Search Trees II	C++, Python	Medium
0096	Unique Binary Search Trees	C++, Python	Medium
0097	Interleaving String	C++, Python	Hard
0098	Validate Binary Search Tree	C++, Python	Medium
0099	Recover Binary Search Tree		Hard
0100	Same Tree	C++, Python	Easy
0101	Symmetric Tree	C++, Python	Easy
0102	Binary Tree Level Order Traversal	C++, Python	Medium
0103	Binary Tree Zigzag Level Order Traversal	C++, Python	Medium
0104	Maximum Depth of Binary Tree	C++, Python	Easy
0105	Construct Binary Tree from Preorder and Inorder Traversal	C++, Python	Medium
0106	Construct Binary Tree from Inorder and Postorder Traversal	C++, Python	Medium
0107	Binary Tree Level Order Traversal II	C++, Python	Easy
0108	Convert Sorted Array to Binary Search Tree	C++, Python	Easy
0109	Convert Sorted List to Binary Search Tree	C++, Python	Medium
0110	Balanced Binary Tree	C++, Python	Easy
0111	Minimum Depth of Binary Tree	C++, Python	Easy
0112	Path Sum	C++, Python	Easy
0113	Path Sum II	C++, Python	Medium
0114	Flatten Binary Tree to Linked List	C++, Python	Medium
0115	Distinct Subsequences	C++, Python	Hard
0116	Populating Next Right Pointers in Each Node	C++, Python	Medium
0117	Populating Next Right Pointers in Each Node II	C++, Python	Medium
0118	Pascal's Triangle	C++, Python	Easy
0119	Pascal's Triangle II	C++, Python	Easy
0120	Triangle	C++, Python	Medium
0121	Best Time to Buy and Sell Stock	C++, Python	Easy
0122	Best Time to Buy and Sell Stock II	C++, Python	Easy
0123	Best Time to Buy and Sell Stock III	C++, Python	Hard
0124	Binary Tree Maximum Path Sum	C++, Python	Hard
0125	Valid Palindrome	C++, Python	Easy
0126	Word Ladder II		Hard
0127	Word Ladder	C++, Python	Medium
0128	Longest Consecutive Sequence	C++, Python	Hard
0129	Sum Root to Leaf Numbers	C++, Python	Medium
0130	Surrounded Regions	C++, Python	Medium
0131	Palindrome Partitioning	C++, Python	Medium
0132	Palindrome Partitioning II	C++, Python	Hard
0133	Clone Graph	C++, Python	Medium
0134	Gas Station	C++, Python	Medium
0135	Candy		Hard
0136	Single Number	C++, Python	Easy
0137	Single Number II		Medium
0138	Copy List with Random Pointer		Medium
0139	Word Break		Medium
0140	Word Break II		Hard
0141	Linked List Cycle	C++	Easy
0142	Linked List Cycle II		Medium
0143	Reorder List		Medium
0144	Binary Tree Preorder Traversal	C++, Python	Medium
0145	Binary Tree Postorder Traversal		Hard
0146	LRU Cache		Hard
0147	Insertion Sort List		Medium
0148	Sort List		Medium
0149	Max Points on a Line		Hard
0150	Evaluate Reverse Polish Notation		Medium
0151	Reverse Words in a String		Medium
0152	Maximum Product Subarray	C++, Python	Medium
0153	Find Minimum in Rotated Sorted Array	C++, Python	Medium
0154	Find Minimum in Rotated Sorted Array II	C++, Python	Hard
0155	Min Stack		Easy
0156	Binary Tree Upside Down		Medium
0157	Read N Characters Given Read4		Easy
0158	Read N Characters Given Read4 II - Call multiple times		Hard
0159	Longest Substring with At Most Two Distinct Characters		Hard
0160	Intersection of Two Linked Lists		Easy
0161	One Edit Distance		Medium
0162	Find Peak Element	C++, Python	Medium
0163	Missing Ranges		Medium
0164	Maximum Gap		Hard
0165	Compare Version Numbers		Medium
0166	Fraction to Recurring Decimal		Medium
0167	Two Sum II - Input array is sorted	C++, Python	Easy
0168	Excel Sheet Column Title		Easy
0169	Majority Element	C++	Easy
0170	Two Sum III - Data structure design		Easy
0171	Excel Sheet Column Number		Easy
0172	Factorial Trailing Zeroes		Easy
0173	Binary Search Tree Iterator		Medium
0174	Dungeon Game		Hard
0175	Combine Two Tables		Easy
0176	Second Highest Salary		Easy
0177	Nth Highest Salary		Medium
0178	Rank Scores		Medium
0179	Largest Number		Medium
0180	Consecutive Numbers		Medium
0181	Employees Earning More Than Their Managers		Easy
0182	Duplicate Emails		Easy
0183	Customers Who Never Order		Easy
0184	Department Highest Salary		Medium
0185	Department Top Three Salaries		Hard
0186	Reverse Words in a String II		Medium
0187	Repeated DNA Sequences		Medium
0188	Best Time to Buy and Sell Stock IV		Hard
0189	Rotate Array	C++	Easy
0190	Reverse Bits	C++	Easy
0191	Number of 1 Bits		Easy
0192	Word Frequency		Medium
0193	Valid Phone Numbers		Easy
0194	Transpose File		Medium
0195	Tenth Line		Easy
0196	Delete Duplicate Emails		Easy
0197	Rising Temperature		Easy
0198	House Robber		Easy
0199	Binary Tree Right Side View		Medium
0200	Number of Islands		Medium
0201	Bitwise AND of Numbers Range		Medium
0202	Happy Number	C++, Python	Easy
0203	Remove Linked List Elements	C++	Easy
0204	Count Primes	C++, Python	Easy
0205	Isomorphic Strings	C++, Python	Easy
0206	Reverse Linked List	C++, Python	Easy
0207	Course Schedule		Medium
0208	Implement Trie (Prefix Tree)		Medium
0209	Minimum Size Subarray Sum	C++, Python	Medium
0210	Course Schedule II		Medium
0211	Add and Search Word - Data structure design		Medium
0212	Word Search II		Hard
0213	House Robber II		Medium
0214	Shortest Palindrome		Hard
0215	Kth Largest Element in an Array		Medium
0216	Combination Sum III	C++, Python	Medium
0217	Contains Duplicate	C++	Easy
0218	The Skyline Problem		Hard
0219	Contains Duplicate II	C++	Easy
0220	Contains Duplicate III		Medium
0221	Maximal Square		Medium
0222	Count Complete Tree Nodes	C++, Python	Medium
0223	Rectangle Area		Medium
0224	Basic Calculator		Hard
0225	Implement Stack using Queues		Easy
0226	Invert Binary Tree		Easy
0227	Basic Calculator II		Medium
0228	Summary Ranges		Medium
0229	Majority Element II	C++	Medium
0230	Kth Smallest Element in a BST		Medium
0231	Power of Two		Easy
0232	Implement Queue using Stacks		Easy
0233	Number of Digit One		Hard
0234	Palindrome Linked List	C++	Easy
0235	Lowest Common Ancestor of a Binary Search Tree		Easy
0236	Lowest Common Ancestor of a Binary Tree		Medium
0237	Delete Node in a Linked List		Easy
0238	Product of Array Except Self		Medium
0239	Sliding Window Maximum		Hard
0240	Search a 2D Matrix II		Medium
0241	Different Ways to Add Parentheses		Medium
0242	Valid Anagram		Easy
0243	Shortest Word Distance		Easy
0244	Shortest Word Distance II		Medium
0245	Shortest Word Distance III		Medium
0246	Strobogrammatic Number		Easy
0247	Strobogrammatic Number II		Medium
0248	Strobogrammatic Number III		Hard
0249	Group Shifted Strings		Medium
0250	Count Univalue Subtrees		Medium
0251	Flatten 2D Vector		Medium
0252	Meeting Rooms		Easy
0253	Meeting Rooms II		Medium
0254	Factor Combinations		Medium
0255	Verify Preorder Sequence in Binary Search Tree		Medium
0256	Paint House		Easy
0257	Binary Tree Paths		Easy
0258	Add Digits		Easy
0259	3Sum Smaller		Medium
0260	Single Number III		Medium
0261	Graph Valid Tree		Medium
0262	Trips and Users		Hard
0263	Ugly Number		Easy
0264	Ugly Number II		Medium
0265	Paint House II		Hard
0266	Palindrome Permutation		Easy
0267	Palindrome Permutation II		Medium
0268	Missing Number		Easy
0269	Alien Dictionary		Hard
0270	Closest Binary Search Tree Value		Easy
0271	Encode and Decode Strings		Medium
0272	Closest Binary Search Tree Value II		Hard
0273	Integer to English Words		Hard
0274	H-Index	C++	Medium
0275	H-Index II	C++	Medium
0276	Paint Fence		Easy
0277	Find the Celebrity		Medium
0278	First Bad Version	C++, Python	Easy
0279	Perfect Squares		Medium
0280	Wiggle Sort		Medium
0281	Zigzag Iterator		Medium
0282	Expression Add Operators		Hard
0283	Move Zeroes		Easy
0284	Peeking Iterator		Medium
0285	Inorder Successor in BST		Medium
0286	Walls and Gates		Medium
0287	Find the Duplicate Number		Medium
0288	Unique Word Abbreviation		Medium
0289	Game of Life	C++	Medium
0290	Word Pattern		Easy
0291	Word Pattern II		Hard
0292	Nim Game		Easy
0293	Flip Game		Easy
0294	Flip Game II		Medium
0295	Find Median from Data Stream		Hard
0296	Best Meeting Point		Hard
0297	Serialize and Deserialize Binary Tree		Hard
0298	Binary Tree Longest Consecutive Sequence		Medium
0299	Bulls and Cows	C++	Medium
0300	Longest Increasing Subsequence		Medium
0301	Remove Invalid Parentheses		Hard
0302	Smallest Rectangle Enclosing Black Pixels		Hard
0303	Range Sum Query - Immutable		Easy
0304	Range Sum Query 2D - Immutable		Medium
0305	Number of Islands II		Hard
0306	Additive Number		Medium
0307	Range Sum Query - Mutable		Medium
0308	Range Sum Query 2D - Mutable		Hard
0309	Best Time to Buy and Sell Stock with Cooldown		Medium
0310	Minimum Height Trees		Medium
0311	Sparse Matrix Multiplication		Medium
0312	Burst Balloons		Hard
0313	Super Ugly Number		Medium
0314	Binary Tree Vertical Order Traversal		Medium
0315	Count of Smaller Numbers After Self		Hard
0316	Remove Duplicate Letters		Hard
0317	Shortest Distance from All Buildings		Hard
0318	Maximum Product of Word Lengths		Medium
0319	Bulb Switcher		Medium
0320	Generalized Abbreviation		Medium
0321	Create Maximum Number		Hard
0322	Coin Change		Medium
0323	Number of Connected Components in an Undirected Graph		Medium
0324	Wiggle Sort II		Medium
0325	Maximum Size Subarray Sum Equals k		Medium
0326	Power of Three		Easy
0327	Count of Range Sum		Hard
0328	Odd Even Linked List	C++	Medium
0329	Longest Increasing Path in a Matrix		Hard
0330	Patching Array		Hard
0331	Verify Preorder Serialization of a Binary Tree		Medium
0332	Reconstruct Itinerary		Medium
0333	Largest BST Subtree		Medium
0334	Increasing Triplet Subsequence		Medium
0335	Self Crossing		Hard
0336	Palindrome Pairs		Hard
0337	House Robber III		Medium
0338	Counting Bits		Medium
0339	Nested List Weight Sum		Easy
0340	Longest Substring with At Most K Distinct Characters		Hard
0341	Flatten Nested List Iterator		Medium
0342	Power of Four		Easy
0343	Integer Break		Medium
0344	Reverse String		Easy
0345	Reverse Vowels of a String		Easy
0346	Moving Average from Data Stream		Easy
0347	Top K Frequent Elements		Medium
0348	Design Tic-Tac-Toe		Medium
0349	Intersection of Two Arrays		Easy
0350	Intersection of Two Arrays II		Easy
0351	Android Unlock Patterns		Medium
0352	Data Stream as Disjoint Intervals		Hard
0353	Design Snake Game		Medium
0354	Russian Doll Envelopes		Hard
0355	Design Twitter		Medium
0356	Line Reflection		Medium
0357	Count Numbers with Unique Digits		Medium
0358	Rearrange String k Distance Apart		Hard
0359	Logger Rate Limiter		Easy
0360	Sort Transformed Array		Medium
0361	Bomb Enemy		Medium
0362	Design Hit Counter		Medium
0363	Max Sum of Rectangle No Larger Than K		Hard
0364	Nested List Weight Sum II		Medium
0365	Water and Jug Problem		Medium
0366	Find Leaves of Binary Tree		Medium
0367	Valid Perfect Square		Easy
0368	Largest Divisible Subset		Medium
0369	Plus One Linked List		Medium
0370	Range Addition		Medium
0371	Sum of Two Integers		Easy
0372	Super Pow		Medium
0373	Find K Pairs with Smallest Sums		Medium
0374	Guess Number Higher or Lower		Easy
0375	Guess Number Higher or Lower II		Medium
0376	Wiggle Subsequence		Medium
0377	Combination Sum IV	C++, Python	Medium
0378	Kth Smallest Element in a Sorted Matrix	C++, Python	Medium
0379	Design Phone Directory		Medium
0380	Insert Delete GetRandom O(1)		Medium
0381	Insert Delete GetRandom O(1) - Duplicates allowed		Hard
0382	Linked List Random Node	C++	Medium
0383	Ransom Note		Easy
0384	Shuffle an Array		Medium
0385	Mini Parser		Medium
0386	Lexicographical Numbers		Medium
0387	First Unique Character in a String		Easy
0388	Longest Absolute File Path		Medium
0389	Find the Difference		Easy
0390	Elimination Game		Medium
0391	Perfect Rectangle		Hard
0392	Is Subsequence		Medium
0393	UTF-8 Validation		Medium
0394	Decode String		Medium
0395	Longest Substring with At Least K Repeating Characters		Medium
0396	Rotate Function		Medium
0397	Integer Replacement		Medium
0398	Random Pick Index		Medium
0399	Evaluate Division		Medium
0400	Nth Digit		Easy
0401	Binary Watch		Easy
0402	Remove K Digits		Medium
0403	Frog Jump		Hard
0404	Sum of Left Leaves		Easy
0405	Convert a Number to Hexadecimal		Easy
0406	Queue Reconstruction by Height		Medium
0407	Trapping Rain Water II		Hard
0408	Valid Word Abbreviation		Easy
0409	Longest Palindrome		Easy
0410	Split Array Largest Sum		Hard
0411	Minimum Unique Word Abbreviation		Hard
0412	Fizz Buzz		Easy
0413	Arithmetic Slices		Medium
0414	Third Maximum Number		Easy
0415	Add Strings		Easy
0416	Partition Equal Subset Sum		Medium
0417	Pacific Atlantic Water Flow		Medium
0418	Sentence Screen Fitting		Medium
0419	Battleships in a Board		Medium
0420	Strong Password Checker		Hard
0421	Maximum XOR of Two Numbers in an Array		Medium
0422	Valid Word Square		Easy
0423	Reconstruct Original Digits from English		Medium
0424	Longest Repeating Character Replacement		Medium
0425	Word Squares		Hard
0432	All O`one Data Structure		Hard
0433	Minimum Genetic Mutation		Medium
0434	Number of Segments in a String		Easy
0435	Non-overlapping Intervals		Medium
0436	Find Right Interval		Medium
0437	Path Sum III		Easy
0438	Find All Anagrams in a String		Easy
0439	Ternary Expression Parser		Medium
0440	K-th Smallest in Lexicographical Order		Hard
0441	Arranging Coins		Easy
0442	Find All Duplicates in an Array		Medium
0443	String Compression		Easy
0444	Sequence Reconstruction		Medium
0445	Add Two Numbers II		Medium
0446	Arithmetic Slices II - Subsequence		Hard
0447	Number of Boomerangs		Easy
0448	Find All Numbers Disappeared in an Array		Easy
0449	Serialize and Deserialize BST		Medium
0450	Delete Node in a BST		Medium
0451	Sort Characters By Frequency		Medium
0452	Minimum Number of Arrows to Burst Balloons		Medium
0453	Minimum Moves to Equal Array Elements		Easy
0454	4Sum II		Medium
0455	Assign Cookies		Easy
0456	132 Pattern		Medium
0457	Circular Array Loop		Medium
0458	Poor Pigs		Hard
0459	Repeated Substring Pattern		Easy
0460	LFU Cache		Hard
0461	Hamming Distance	C++	Easy
0462	Minimum Moves to Equal Array Elements II		Medium
0463	Island Perimeter		Easy
0464	Can I Win		Medium
0465	Optimal Account Balancing		Hard
0466	Count The Repetitions		Hard
0467	Unique Substrings in Wraparound String		Medium
0468	Validate IP Address		Medium
0469	Convex Polygon		Medium
0471	Encode String with Shortest Length		Hard
0472	Concatenated Words		Hard
0473	Matchsticks to Square		Medium
0474	Ones and Zeroes		Medium
0475	Heaters		Easy
0476	Number Complement	C++	Easy
0477	Total Hamming Distance	C++	Medium
0479	Largest Palindrome Product		Hard
0480	Sliding Window Median		Hard
0481	Magical String		Medium
0482	License Key Formatting		Easy
0483	Smallest Good Base		Hard
0484	Find Permutation		Medium
0485	Max Consecutive Ones		Easy
0486	Predict the Winner		Medium
0487	Max Consecutive Ones II		Medium
0488	Zuma Game		Hard
0490	The Maze		Medium
0491	Increasing Subsequences		Medium
0492	Construct the Rectangle		Easy
0493	Reverse Pairs		Hard
0494	Target Sum		Medium
0495	Teemo Attacking		Medium
0496	Next Greater Element I		Easy
0498	Diagonal Traverse		Medium
0499	The Maze III		Hard
0500	Keyboard Row		Easy
0501	Find Mode in Binary Search Tree		Easy
0502	IPO		Hard
0503	Next Greater Element II		Medium
0504	Base 7		Easy
0505	The Maze II		Medium
0506	Relative Ranks		Easy
0507	Perfect Number		Easy
0508	Most Frequent Subtree Sum		Medium
0510	Inorder Successor in BST II		Medium
0513	Find Bottom Left Tree Value		Medium
0514	Freedom Trail		Hard
0515	Find Largest Value in Each Tree Row		Medium
0516	Longest Palindromic Subsequence		Medium
0517	Super Washing Machines		Hard
0518	Coin Change 2		Medium
0520	Detect Capital		Easy
0521	Longest Uncommon Subsequence I		Easy
0522	Longest Uncommon Subsequence II		Medium
0523	Continuous Subarray Sum		Medium
0524	Longest Word in Dictionary through Deleting		Medium
0525	Contiguous Array		Medium
0526	Beautiful Arrangement		Medium
0527	Word Abbreviation		Hard
0529	Minesweeper		Medium
0530	Minimum Absolute Difference in BST		Easy
0531	Lonely Pixel I		Medium
0532	K-diff Pairs in an Array		Easy
0533	Lonely Pixel II		Medium
0535	Encode and Decode TinyURL		Medium
0536	Construct Binary Tree from String		Medium
0537	Complex Number Multiplication		Medium
0538	Convert BST to Greater Tree		Easy
0539	Minimum Time Difference		Medium
0540	Single Element in a Sorted Array		Medium
0541	Reverse String II		Easy
0542	01 Matrix		Medium
0543	Diameter of Binary Tree		Easy
0544	Output Contest Matches		Medium
0545	Boundary of Binary Tree		Medium
0546	Remove Boxes		Hard
0547	Friend Circles		Medium
0548	Split Array with Equal Sum		Medium
0549	Binary Tree Longest Consecutive Sequence II		Medium
0551	Student Attendance Record I		Easy
0552	Student Attendance Record II		Hard
0553	Optimal Division		Medium
0554	Brick Wall		Medium
0555	Split Concatenated Strings		Medium
0556	Next Greater Element III		Medium
0557	Reverse Words in a String III		Easy
0560	Subarray Sum Equals K		Medium
0561	Array Partition I		Easy
0562	Longest Line of Consecutive One in Matrix		Medium
0563	Binary Tree Tilt		Easy
0564	Find the Closest Palindrome		Hard
0565	Array Nesting		Medium
0566	Reshape the Matrix		Easy
0567	Permutation in String		Medium
0568	Maximum Vacation Days		Hard
0569	Median Employee Salary		Hard
0570	Managers with at Least 5 Direct Reports		Medium
0571	Find Median Given Frequency of Numbers		Hard
0572	Subtree of Another Tree		Easy
0573	Squirrel Simulation		Medium
0574	Winning Candidate		Medium
0575	Distribute Candies		Easy
0576	Out of Boundary Paths		Medium
0577	Employee Bonus		Easy
0578	Get Highest Answer Rate Question		Medium
0579	Find Cumulative Salary of an Employee		Hard
0580	Count Student Number in Departments		Medium
0581	Shortest Unsorted Continuous Subarray		Easy
0582	Kill Process		Medium
0583	Delete Operation for Two Strings		Medium
0584	Find Customer Referee		Easy
0585	Investments in 2016		Medium
0586	Customer Placing the Largest Number of Orders		Easy
0587	Erect the Fence		Hard
0588	Design In-Memory File System		Hard
0591	Tag Validator		Hard
0592	Fraction Addition and Subtraction		Medium
0593	Valid Square		Medium
0594	Longest Harmonious Subsequence		Easy
0595	Big Countries		Easy
0596	Classes More Than 5 Students		Easy
0597	Friend Requests I: Overall Acceptance Rate		Easy
0598	Range Addition II		Easy
0599	Minimum Index Sum of Two Lists	C++	Easy
0600	Non-negative Integers without Consecutive Ones		Hard
0601	Human Traffic of Stadium		Hard
0602	Friend Requests II: Who Has the Most Friends		Medium
0603	Consecutive Available Seats		Easy
0604	Design Compressed String Iterator		Easy
0605	Can Place Flowers		Easy
0606	Construct String from Binary Tree		Easy
0607	Sales Person		Easy
0608	Tree Node		Medium
0609	Find Duplicate File in System		Medium
0610	Triangle Judgement		Easy
0611	Valid Triangle Number		Medium
0612	Shortest Distance in a Plane		Medium
0613	Shortest Distance in a Line		Easy
0614	Second Degree Follower		Medium
0615	Average Salary: Departments VS Company		Hard
0616	Add Bold Tag in String		Medium
0617	Merge Two Binary Trees		Easy
0618	Students Report By Geography		Hard
0619	Biggest Single Number		Easy
0620	Not Boring Movies		Easy
0621	Task Scheduler		Medium
0623	Add One Row to Tree		Medium
0624	Maximum Distance in Arrays		Easy
0625	Minimum Factorization		Medium
0626	Exchange Seats		Medium
0627	Swap Salary		Easy
0628	Maximum Product of Three Numbers		Easy
0629	K Inverse Pairs Array		Hard
0630	Course Schedule III		Hard
0631	Design Excel Sum Formula		Hard
0632	Smallest Range		Hard
0633	Sum of Square Numbers		Easy
0634	Find the Derangement of An Array		Medium
0635	Design Log Storage System		Medium
0636	Exclusive Time of Functions		Medium
0637	Average of Levels in Binary Tree		Easy
0638	Shopping Offers		Medium
0639	Decode Ways II		Hard
0640	Solve the Equation		Medium
0642	Design Search Autocomplete System		Hard
0643	Maximum Average Subarray I		Easy
0644	Maximum Average Subarray II		Hard
0645	Set Mismatch		Easy
0646	Maximum Length of Pair Chain		Medium
0647	Palindromic Substrings		Medium
0648	Replace Words		Medium
0649	Dota2 Senate		Medium
0650	2 Keys Keyboard		Medium
0651	4 Keys Keyboard		Medium
0652	Find Duplicate Subtrees		Medium
0653	Two Sum IV - Input is a BST		Easy
0654	Maximum Binary Tree		Medium
0655	Print Binary Tree		Medium
0656	Coin Path		Hard
0657	Robot Return to Origin		Easy
0658	Find K Closest Elements		Medium
0659	Split Array into Consecutive Subsequences		Medium
0660	Remove 9		Hard
0661	Image Smoother		Easy
0662	Maximum Width of Binary Tree		Medium
0663	Equal Tree Partition		Medium
0664	Strange Printer		Hard
0665	Non-decreasing Array		Easy
0666	Path Sum IV		Medium
0667	Beautiful Arrangement II		Medium
0668	Kth Smallest Number in Multiplication Table		Hard
0669	Trim a Binary Search Tree		Easy
0670	Maximum Swap		Medium
0671	Second Minimum Node In a Binary Tree		Easy
0672	Bulb Switcher II		Medium
0673	Number of Longest Increasing Subsequence		Medium
0674	Longest Continuous Increasing Subsequence		Easy
0675	Cut Off Trees for Golf Event		Hard
0676	Implement Magic Dictionary		Medium
0677	Map Sum Pairs		Medium
0678	Valid Parenthesis String		Medium
0679	24 Game		Hard
0680	Valid Palindrome II		Easy
0681	Next Closest Time		Medium
0682	Baseball Game		Easy
0683	K Empty Slots		Hard
0684	Redundant Connection		Medium
0685	Redundant Connection II		Hard
0686	Repeated String Match		Easy
0687	Longest Univalue Path		Easy
0688	Knight Probability in Chessboard		Medium
0689	Maximum Sum of 3 Non-Overlapping Subarrays		Hard
0690	Employee Importance		Easy
0691	Stickers to Spell Word		Hard
0692	Top K Frequent Words		Medium
0693	Binary Number with Alternating Bits		Easy
0694	Number of Distinct Islands		Medium
0695	Max Area of Island		Medium
0696	Count Binary Substrings		Easy
0697	Degree of an Array		Easy
0698	Partition to K Equal Sum Subsets		Medium
0699	Falling Squares		Hard
0711	Number of Distinct Islands II		Hard
0712	Minimum ASCII Delete Sum for Two Strings		Medium
0713	Subarray Product Less Than K		Medium
0714	Best Time to Buy and Sell Stock with Transaction Fee		Medium
0715	Range Module		Hard
0716	Max Stack		Easy
0717	1-bit and 2-bit Characters		Easy
0718	Maximum Length of Repeated Subarray		Medium
0719	Find K-th Smallest Pair Distance		Hard
0720	Longest Word in Dictionary		Easy
0721	Accounts Merge		Medium
0722	Remove Comments		Medium
0723	Candy Crush		Medium
0724	Find Pivot Index		Easy
0725	Split Linked List in Parts	C++	Medium
0726	Number of Atoms		Hard
0727	Minimum Window Subsequence		Hard
0728	Self Dividing Numbers		Easy
0729	My Calendar I		Medium
0730	Count Different Palindromic Subsequences		Hard
0731	My Calendar II		Medium
0732	My Calendar III		Hard
0733	Flood Fill		Easy
0734	Sentence Similarity		Easy
0735	Asteroid Collision		Medium
0736	Parse Lisp Expression		Hard
0737	Sentence Similarity II		Medium
0738	Monotone Increasing Digits		Medium
0739	Daily Temperatures		Medium
0740	Delete and Earn		Medium
0741	Cherry Pickup		Hard
0709	To Lower Case		Easy
0742	Closest Leaf in a Binary Tree		Medium
0743	Network Delay Time		Medium
0744	Find Smallest Letter Greater Than Target	C++, Python	Easy
0745	Prefix and Suffix Search		Hard
0746	Min Cost Climbing Stairs		Easy
0747	Largest Number At Least Twice of Others		Easy
0748	Shortest Completing Word		Easy
0749	Contain Virus		Hard
0750	Number Of Corner Rectangles		Medium
0751	IP to CIDR		Easy
0752	Open the Lock		Medium
0753	Cracking the Safe		Hard
0754	Reach a Number		Easy
0755	Pour Water		Medium
0756	Pyramid Transition Matrix		Medium
0426	Convert Binary Search Tree to Sorted Doubly Linked List		Medium
0757	Set Intersection Size At Least Two		Hard
0758	Bold Words in String		Easy
0759	Employee Free Time		Hard
0760	Find Anagram Mappings		Easy
0761	Special Binary String		Hard
0429	N-ary Tree Level Order Traversal		Easy
0428	Serialize and Deserialize N-ary Tree		Hard
0430	Flatten a Multilevel Doubly Linked List		Medium
0762	Prime Number of Set Bits in Binary Representation	C++	Easy
0763	Partition Labels		Medium
0764	Largest Plus Sign		Medium
0765	Couples Holding Hands		Hard
0431	Encode N-ary Tree to Binary Tree		Hard
0427	Construct Quad Tree		Easy
0558	Quad Tree Intersection		Easy
0559	Maximum Depth of N-ary Tree		Easy
0589	N-ary Tree Preorder Traversal		Easy
0590	N-ary Tree Postorder Traversal		Easy
0766	Toeplitz Matrix		Easy
0767	Reorganize String		Medium
0768	Max Chunks To Make Sorted II		Hard
0769	Max Chunks To Make Sorted		Medium
0770	Basic Calculator IV		Hard
0771	Jewels and Stones		Easy
0700	Search in a Binary Search Tree		Easy
0701	Insert into a Binary Search Tree		Medium
0772	Basic Calculator III		Hard
0702	Search in a Sorted Array of Unknown Size		Medium
0773	Sliding Puzzle		Hard
0774	Minimize Max Distance to Gas Station		Hard
0703	Kth Largest Element in a Stream		Easy
0775	Global and Local Inversions		Medium
0776	Split BST		Medium
0704	Binary Search		Easy
0777	Swap Adjacent in LR String		Medium
0778	Swim in Rising Water		Hard
0779	K-th Symbol in Grammar		Medium
0780	Reaching Points		Hard
0781	Rabbits in Forest		Medium
0782	Transform to Chessboard		Hard
0783	Minimum Distance Between BST Nodes		Easy
0784	Letter Case Permutation		Easy
0785	Is Graph Bipartite?		Medium
0786	K-th Smallest Prime Fraction		Hard
0787	Cheapest Flights Within K Stops		Medium
0788	Rotated Digits		Easy
0789	Escape The Ghosts		Medium
0790	Domino and Tromino Tiling		Medium
0791	Custom Sort String		Medium
0792	Number of Matching Subsequences		Medium
0793	Preimage Size of Factorial Zeroes Function		Hard
0794	Valid Tic-Tac-Toe State		Medium
0795	Number of Subarrays with Bounded Maximum		Medium
0796	Rotate String		Easy
0797	All Paths From Source to Target		Medium
0798	Smallest Rotation with Highest Score		Hard
0799	Champagne Tower		Medium
0705	Design HashSet		Easy
0706	Design HashMap		Easy
0800	Similar RGB Color		Easy
0801	Minimum Swaps To Make Sequences Increasing		Medium
0802	Find Eventual Safe States		Medium
0803	Bricks Falling When Hit		Hard
0804	Unique Morse Code Words		Easy
0805	Split Array With Same Average		Hard
0806	Number of Lines To Write String		Easy
0807	Max Increase to Keep City Skyline		Medium
0808	Soup Servings		Medium
0809	Expressive Words		Medium
0810	Chalkboard XOR Game		Hard
0811	Subdomain Visit Count		Easy
0812	Largest Triangle Area		Easy
0813	Largest Sum of Averages		Medium
0814	Binary Tree Pruning		Medium
0815	Bus Routes		Hard
0816	Ambiguous Coordinates		Medium
0817	Linked List Components	C++	Medium
0818	Race Car		Hard
0819	Most Common Word		Easy
0707	Design Linked List		Easy
0820	Short Encoding of Words		Medium
0821	Shortest Distance to a Character		Easy
0822	Card Flipping Game		Medium
0823	Binary Trees With Factors		Medium
0708	Insert into a Cyclic Sorted List		Medium
0824	Goat Latin		Easy
0825	Friends Of Appropriate Ages		Medium
0826	Most Profit Assigning Work		Medium
0827	Making A Large Island		Hard
0828	Unique Letter String		Hard
0829	Consecutive Numbers Sum		Hard
0830	Positions of Large Groups		Easy
0831	Masking Personal Information		Medium
0641	Design Circular Deque		Medium
0622	Design Circular Queue		Medium
0832	Flipping an Image	C++, Python	Easy
0833	Find And Replace in String		Medium
0834	Sum of Distances in Tree		Hard
0835	Image Overlap		Medium
0489	Robot Room Cleaner		Hard
0836	Rectangle Overlap		Easy
0837	New 21 Game		Medium
0838	Push Dominoes		Medium
0839	Similar String Groups		Hard
0840	Magic Squares In Grid		Easy
0841	Keys and Rooms		Medium
0842	Split Array into Fibonacci Sequence		Medium
0843	Guess the Word		Hard
0844	Backspace String Compare		Easy
0845	Longest Mountain in Array		Medium
0846	Hand of Straights		Medium
0847	Shortest Path Visiting All Nodes	C++	Hard
0848	Shifting Letters		Medium
0849	Maximize Distance to Closest Person		Easy
0850	Rectangle Area II		Hard
0851	Loud and Rich		Medium
0852	Peak Index in a Mountain Array		Easy
0853	Car Fleet		Medium
0854	K-Similar Strings		Hard
0855	Exam Room		Medium
0856	Score of Parentheses		Medium
0857	Minimum Cost to Hire K Workers		Hard
0858	Mirror Reflection		Medium
0859	Buddy Strings		Easy
0860	Lemonade Change		Easy
0861	Score After Flipping Matrix		Medium
0862	Shortest Subarray with Sum at Least K		Hard
0863	All Nodes Distance K in Binary Tree		Medium
0710	Random Pick with Blacklist		Hard
0864	Shortest Path to Get All Keys		Hard
0865	Smallest Subtree with all the Deepest Nodes		Medium
0866	Prime Palindrome		Medium
0867	Transpose Matrix		Easy
0868	Binary Gap		Easy
0869	Reordered Power of 2		Medium
0870	Advantage Shuffle		Medium
0871	Minimum Number of Refueling Stops		Hard
0470	Implement Rand10() Using Rand7()		Medium
0872	Leaf-Similar Trees		Easy
0873	Length of Longest Fibonacci Subsequence		Medium
0874	Walking Robot Simulation		Easy
0875	Koko Eating Bananas	C++, Python	Medium
0876	Middle of the Linked List	C++	Easy
0877	Stone Game		Medium
0878	Nth Magical Number		Hard
0879	Profitable Schemes		Hard
0528	Random Pick with Weight		Medium
0519	Random Flip Matrix		Medium
0497	Random Point in Non-overlapping Rectangles		Medium
0478	Generate Random Point in a Circle		Medium
0880	Decoded String at Index		Medium
0881	Boats to Save People		Medium
0882	Reachable Nodes In Subdivided Graph		Hard
0883	Projection Area of 3D Shapes		Easy
0884	Uncommon Words from Two Sentences		Easy
0885	Spiral Matrix III		Medium
0886	Possible Bipartition		Medium
0887	Super Egg Drop		Hard
0888	Fair Candy Swap		Easy
0889	Construct Binary Tree from Preorder and Postorder Traversal	C++, Python	Medium
0890	Find and Replace Pattern		Medium
0891	Sum of Subsequence Widths		Hard
0892	Surface Area of 3D Shapes		Easy
0893	Groups of Special-Equivalent Strings		Easy
0894	All Possible Full Binary Trees		Medium
0895	Maximum Frequency Stack		Hard
0896	Monotonic Array		Easy
0897	Increasing Order Search Tree		Easy
0898	Bitwise ORs of Subarrays		Medium
0899	Orderly Queue		Hard
0900	RLE Iterator		Medium
0901	Online Stock Span		Medium
0902	Numbers At Most N Given Digit Set		Hard
0903	Valid Permutations for DI Sequence		Hard
0904	Fruit Into Baskets		Medium
0905	Sort Array By Parity	C++, Python	Easy
0906	Super Palindromes		Hard
0907	Sum of Subarray Minimums		Medium
0908	Smallest Range I		Easy
0909	Snakes and Ladders		Medium
0910	Smallest Range II		Medium
0911	Online Election		Medium
0912	Sort an Array		Medium
0913	Cat and Mouse		Hard
0914	X of a Kind in a Deck of Cards		Easy
0915	Partition Array into Disjoint Intervals		Medium
0916	Word Subsets		Medium
0917	Reverse Only Letters		Easy
0918	Maximum Sum Circular Subarray		Medium
0919	Complete Binary Tree Inserter		Medium
0920	Number of Music Playlists		Hard
0921	Minimum Add to Make Parentheses Valid		Medium
0922	Sort Array By Parity II		Easy
0923	3Sum With Multiplicity		Medium
0924	Minimize Malware Spread		Hard
0925	Long Pressed Name		Easy
0926	Flip String to Monotone Increasing		Medium
0927	Three Equal Parts		Hard
0928	Minimize Malware Spread II		Hard
0929	Unique Email Addresses		Easy
0930	Binary Subarrays With Sum		Medium
0931	Minimum Falling Path Sum		Medium
0932	Beautiful Array		Medium
0933	Number of Recent Calls		Easy
0934	Shortest Bridge		Medium
0935	Knight Dialer		Medium
0936	Stamping The Sequence		Hard
0937	Reorder Log Files		Easy
0938	Range Sum of BST		Easy
0939	Minimum Area Rectangle		Medium
0940	Distinct Subsequences II		Hard
0941	Valid Mountain Array		Easy
0942	DI String Match		Easy
0943	Find the Shortest Superstring		Hard
0944	Delete Columns to Make Sorted		Easy
0945	Minimum Increment to Make Array Unique		Medium
0946	Validate Stack Sequences		Medium
0947	Most Stones Removed with Same Row or Column		Medium
0948	Bag of Tokens		Medium
0949	Largest Time for Given Digits		Easy
0950	Reveal Cards In Increasing Order		Medium
0951	Flip Equivalent Binary Trees		Medium
0952	Largest Component Size by Common Factor		Hard
0953	Verifying an Alien Dictionary		Easy
0954	Array of Doubled Pairs		Medium
0955	Delete Columns to Make Sorted II		Medium
0956	Tallest Billboard		Hard
0957	Prison Cells After N Days		Medium
0958	Check Completeness of a Binary Tree		Medium
0959	Regions Cut By Slashes		Medium
0960	Delete Columns to Make Sorted III		Hard
0961	N-Repeated Element in Size 2N Array		Easy
0962	Maximum Width Ramp		Medium
0963	Minimum Area Rectangle II		Medium
0964	Least Operators to Express Number		Hard
0965	Univalued Binary Tree		Easy
0966	Vowel Spellchecker		Medium
0967	Numbers With Same Consecutive Differences		Medium
0968	Binary Tree Cameras		Hard
0969	Pancake Sorting		Medium
0970	Powerful Integers		Easy
0971	Flip Binary Tree To Match Preorder Traversal		Medium
0972	Equal Rational Numbers		Hard
0509	Fibonacci Number		Easy
0973	K Closest Points to Origin		Medium
0974	Subarray Sums Divisible by K		Medium
0975	Odd Even Jump		Hard
0976	Largest Perimeter Triangle		Easy
0977	Squares of a Sorted Array	C++, Python	Easy
0978	Longest Turbulent Subarray		Medium
0979	Distribute Coins in Binary Tree		Medium
0980	Unique Paths III		Hard
0981	Time Based Key-Value Store		Medium
0982	Triples with Bitwise AND Equal To Zero		Hard
0983	Minimum Cost For Tickets		Medium
0984	String Without AAA or BBB		Medium
0985	Sum of Even Numbers After Queries		Easy
0986	Interval List Intersections	C++	Medium
0987	Vertical Order Traversal of a Binary Tree		Medium
0988	Smallest String Starting From Leaf		Medium
0989	Add to Array-Form of Integer		Easy
0990	Satisfiability of Equality Equations		Medium
0991	Broken Calculator		Medium
0992	Subarrays with K Different Integers		Hard
0993	Cousins in Binary Tree		Easy
0994	Rotting Oranges		Easy
0995	Minimum Number of K Consecutive Bit Flips		Hard
0996	Number of Squareful Arrays		Hard
0997	Find the Town Judge		Easy
0998	Maximum Binary Tree II		Medium
0999	Available Captures for Rook		Easy
1000	Minimum Cost to Merge Stones		Hard
1001	Grid Illumination		Hard
1002	Find Common Characters		Easy
1003	Check If Word Is Valid After Substitutions		Medium
1004	Max Consecutive Ones III		Medium
1005	Maximize Sum Of Array After K Negations		Easy
1006	Clumsy Factorial		Medium
1007	Minimum Domino Rotations For Equal Row		Medium
1008	Construct Binary Search Tree from Preorder Traversal		Medium
1009	Complement of Base 10 Integer		Easy
1010	Pairs of Songs With Total Durations Divisible by 60		Easy
1011	Capacity To Ship Packages Within D Days		Medium
1012	Numbers With Repeated Digits		Hard
1013	Partition Array Into Three Parts With Equal Sum		Easy
1014	Best Sightseeing Pair		Medium
1015	Smallest Integer Divisible by K		Medium
1016	Binary String With Substrings Representing 1 To N		Medium
1017	Convert to Base -2		Medium
1018	Binary Prefix Divisible By 5		Easy
1019	Next Greater Node In Linked List		Medium
1020	Number of Enclaves		Medium
1021	Remove Outermost Parentheses		Easy
1022	Sum of Root To Leaf Binary Numbers		Easy
1023	Camelcase Matching		Medium
1024	Video Stitching		Medium
1025	Divisor Game		Easy
1027	Longest Arithmetic Sequence		Medium
1026	Maximum Difference Between Node and Ancestor		Medium
1028	Recover a Tree From Preorder Traversal		Hard
1030	Matrix Cells in Distance Order		Easy
1029	Two City Scheduling		Easy
1031	Maximum Sum of Two Non-Overlapping Subarrays		Medium
1032	Stream of Characters		Hard
1033	Moving Stones Until Consecutive		Easy
1034	Coloring A Border		Medium
1035	Uncrossed Lines		Medium
1036	Escape a Large Maze		Hard
1039	Minimum Score Triangulation of Polygon		Medium
1040	Moving Stones Until Consecutive II		Medium
1038	Binary Search Tree to Greater Sum Tree		Medium
1037	Valid Boomerang		Easy
1041	Robot Bounded In Circle		Easy
1042	Flower Planting With No Adjacent		Easy
1043	Partition Array for Maximum Sum		Medium
1044	Longest Duplicate Substring		Hard
1046	Last Stone Weight		Easy
1047	Remove All Adjacent Duplicates In String		Easy
1048	Longest String Chain		Medium
1049	Last Stone Weight II		Medium
1045	Customers Who Bought All Products		Medium
1050	Actors and Directors Who Cooperated At Least Three Times		Easy