Previous Questions

Apple

ID	Questions
1	Two Sum
2	Add Two Numbers
3	Longest Substring Without Repeating Characters
4	Median of Two Sorted Arrays
5	Longest Palindromic Substring
6	Zigzag Conversion
7	Reverse Integer
8	String to Integer (atoi)
9	Palindrome Number
10	Regular Expression Matching
11	Container With Most Water
12	Integer to Roman
13	Roman to Integer
14	Longest Common Prefix
15	3Sum
16	3Sum Closest
17	Letter Combinations of a Phone Number
18	4Sum
19	Remove Nth Node From End of List
20	Valid Parentheses
21	Merge Two Sorted Lists
22	Generate Parentheses
23	Merge k Sorted Lists
24	Swap Nodes in Pairs
25	Reverse Nodes in k-Group
26	Remove Duplicates from Sorted Array
27	Remove Element
28	Find the Index of the First Occurrence in a String
29	Divide Two Integers
30	Substring with Concatenation of All Words
31	Next Permutation
32	Longest Valid Parentheses
33	Search in Rotated Sorted Array
34	Find First and Last Position of Element in Sorted Array
35	Search Insert Position
36	Valid Sudoku
37	Sudoku Solver
38	Count and Say
39	Combination Sum
40	Combination Sum II
41	First Missing Positive
42	Trapping Rain Water
43	Multiply Strings
44	Wildcard Matching
45	Jump Game II
46	Permutations
47	Permutations II
48	Rotate Image
49	Group Anagrams
50	Pow(x, n)
51	N-Queens
53	Maximum Subarray
54	Spiral Matrix
55	Jump Game
56	Merge Intervals
57	Insert Interval
58	Length of Last Word
59	Spiral Matrix II
61	Rotate List
62	Unique Paths
63	Unique Paths II
64	Minimum Path Sum
65	Valid Number
66	Plus One
67	Add Binary
68	Text Justification
69	Sqrt(x)
70	Climbing Stairs
71	Simplify Path
72	Edit Distance
73	Set Matrix Zeroes
74	Search a 2D Matrix
75	Sort Colors
76	Minimum Window Substring
77	Combinations
78	Subsets
79	Word Search
80	Remove Duplicates from Sorted Array II
81	Search in Rotated Sorted Array II
82	Remove Duplicates from Sorted List II
83	Remove Duplicates from Sorted List
84	Largest Rectangle in Histogram
85	Maximal Rectangle
86	Partition List
87	Scramble String
88	Merge Sorted Array
89	Gray Code
90	Subsets II
91	Decode Ways
92	Reverse Linked List II
93	Restore IP Addresses
94	Binary Tree Inorder Traversal
95	Unique Binary Search Trees II
96	Unique Binary Search Trees
97	Interleaving String
98	Validate Binary Search Tree
99	Recover Binary Search Tree
100	Same Tree
101	Symmetric Tree
102	Binary Tree Level Order Traversal
103	Binary Tree Zigzag Level Order Traversal
104	Maximum Depth of Binary Tree
105	Construct Binary Tree from Preorder and Inorder Traversal
108	Convert Sorted Array to Binary Search Tree
109	Convert Sorted List to Binary Search Tree
113	Path Sum II
114	Flatten Binary Tree to Linked List
115	Distinct Subsequences
116	Populating Next Right Pointers in Each Node
118	Pascal’s Triangle
119	Pascal’s Triangle II
120	Triangle
121	Best Time to Buy and Sell Stock
122	Best Time to Buy and Sell Stock II
123	Best Time to Buy and Sell Stock III
124	Binary Tree Maximum Path Sum
125	Valid Palindrome
126	Word Ladder II
127	Word Ladder
128	Longest Consecutive Sequence
129	Sum Root to Leaf Numbers
130	Surrounded Regions
131	Palindrome Partitioning
132	Palindrome Partitioning II
133	Clone Graph
134	Gas Station
136	Single Number
137	Single Number II
138	Copy List with Random Pointer
139	Word Break
140	Word Break II
141	Linked List Cycle
142	Linked List Cycle II
143	Reorder List
144	Binary Tree Preorder Traversal
145	Binary Tree Postorder Traversal
146	LRU Cache
148	Sort List
149	Max Points on a Line
151	Reverse Words in a String
152	Maximum Product Subarray
153	Find Minimum in Rotated Sorted Array
154	Find Minimum in Rotated Sorted Array II
155	Min Stack
158	Read N Characters Given read4 II - Call Multiple Times
160	Intersection of Two Linked Lists
162	Find Peak Element
165	Compare Version Numbers
167	Two Sum II - Input Array Is Sorted
168	Excel Sheet Column Title
169	Majority Element
171	Excel Sheet Column Number
173	Binary Search Tree Iterator
174	Dungeon Game
175	Combine Two Tables
176	Second Highest Salary
178	Rank Scores
179	Largest Number
180	Consecutive Numbers
183	Customers Who Never Order
184	Department Highest Salary
186	Reverse Words in a String II
188	Best Time to Buy and Sell Stock IV
189	Rotate Array
190	Reverse Bits
191	Number of 1 Bits
193	Valid Phone Numbers
196	Delete Duplicate Emails
198	House Robber
199	Binary Tree Right Side View
200	Number of Islands
201	Bitwise AND of Numbers Range
202	Happy Number
203	Remove Linked List Elements
204	Count Primes
205	Isomorphic Strings
206	Reverse Linked List
207	Course Schedule
208	Implement Trie (Prefix Tree)
209	Minimum Size Subarray Sum
210	Course Schedule II
211	Design Add and Search Words Data Structure
212	Word Search II
215	Kth Largest Element in an Array
216	Combination Sum III
217	Contains Duplicate
218	The Skyline Problem
219	Contains Duplicate II
220	Contains Duplicate III
221	Maximal Square
222	Count Complete Tree Nodes
223	Rectangle Area
224	Basic Calculator
225	Implement Stack using Queues
226	Invert Binary Tree
227	Basic Calculator II
229	Majority Element II
230	Kth Smallest Element in a BST
231	Power of Two
232	Implement Queue using Stacks
233	Number of Digit One
234	Palindrome Linked List
235	Lowest Common Ancestor of a Binary Search Tree
236	Lowest Common Ancestor of a Binary Tree
237	Delete Node in a Linked List
238	Product of Array Except Self
239	Sliding Window Maximum
240	Search a 2D Matrix II
242	Valid Anagram
252	Meeting Rooms
253	Meeting Rooms II
257	Binary Tree Paths
258	Add Digits
259	3Sum Smaller
268	Missing Number
269	Alien Dictionary
273	Integer to English Words
274	H-Index
277	Find the Celebrity
278	First Bad Version
279	Perfect Squares
283	Move Zeroes
284	Peeking Iterator
285	Inorder Successor in BST
287	Find the Duplicate Number
290	Word Pattern
295	Find Median from Data Stream
297	Serialize and Deserialize Binary Tree
300	Longest Increasing Subsequence
301	Remove Invalid Parentheses
311	Sparse Matrix Multiplication
312	Burst Balloons
315	Count of Smaller Numbers After Self
316	Remove Duplicate Letters
322	Coin Change
325	Maximum Size Subarray Sum Equals k
326	Power of Three
328	Odd Even Linked List
329	Longest Increasing Path in a Matrix
334	Increasing Triplet Subsequence
336	Palindrome Pairs
341	Flatten Nested List Iterator
342	Power of Four
343	Integer Break
344	Reverse String
345	Reverse Vowels of a String
346	Moving Average from Data Stream
347	Top K Frequent Elements
348	Design Tic-Tac-Toe
349	Intersection of Two Arrays
350	Intersection of Two Arrays II
352	Data Stream as Disjoint Intervals
355	Design Twitter
357	Count Numbers with Unique Digits
359	Logger Rate Limiter
362	Design Hit Counter
367	Valid Perfect Square
368	Largest Divisible Subset
371	Sum of Two Integers
373	Find K Pairs with Smallest Sums
374	Guess Number Higher or Lower
376	Wiggle Subsequence
377	Combination Sum IV
380	Insert Delete GetRandom O(1)
381	Insert Delete GetRandom O(1) - Duplicates allowed
383	Ransom Note
384	Shuffle an Array
387	First Unique Character in a String
389	Find the Difference
392	Is Subsequence
393	UTF-8 Validation
394	Decode String
395	Longest Substring with At Least K Repeating Characters
399	Evaluate Division
400	Nth Digit
402	Remove K Digits
407	Trapping Rain Water II
409	Longest Palindrome
410	Split Array Largest Sum
412	Fizz Buzz
415	Add Strings
416	Partition Equal Subset Sum
417	Pacific Atlantic Water Flow
419	Battleships in a Board
420	Strong Password Checker
421	Maximum XOR of Two Numbers in an Array
424	Longest Repeating Character Replacement
433	Minimum Genetic Mutation
435	Non-overlapping Intervals
438	Find All Anagrams in a String
442	Find All Duplicates in an Array
443	String Compression
445	Add Two Numbers II
448	Find All Numbers Disappeared in an Array
450	Delete Node in a BST
451	Sort Characters By Frequency
452	Minimum Number of Arrows to Burst Balloons
455	Assign Cookies
456	132 Pattern
459	Repeated Substring Pattern
460	LFU Cache
462	Minimum Moves to Equal Array Elements II
463	Island Perimeter
465	Optimal Account Balancing
468	Validate IP Address
473	Matchsticks to Square
474	Ones and Zeroes
475	Heaters
476	Number Complement
485	Max Consecutive Ones
486	Predict the Winner
493	Reverse Pairs
494	Target Sum
496	Next Greater Element I
503	Next Greater Element II
508	Most Frequent Subtree Sum
516	Longest Palindromic Subsequence
518	Coin Change II
523	Continuous Subarray Sum
525	Contiguous Array
528	Swapping Nodes in a Linked List
532	K-diff Pairs in an Array
540	Single Element in a Sorted Array
541	Reverse String II
542	01 Matrix
543	Diameter of Binary Tree
545	Boundary of Binary Tree
547	Number of Provinces
556	Next Greater Element III
557	Reverse Words in a String III
560	Subarray Sum Equals K
565	Array Nesting
566	Reshape the Matrix
567	Permutation in String
570	Managers with at Least 5 Direct Reports
572	Subtree of Another Tree
583	Delete Operation for Two Strings
584	Find Customer Referee
586	Customer Placing the Largest Number of Orders
595	Big Countries
605	Can Place Flowers
609	Find Duplicate File in System
610	Triangle Judgement
611	Valid Triangle Number
617	Merge Two Binary Trees
619	Biggest Single Number
620	Not Boring Movies
621	Task Scheduler
627	Swap Salary
629	K Inverse Pairs Array
632	Smallest Range Covering Elements from K Lists
633	Sum of Square Numbers
642	Design Search Autocomplete System
643	Maximum Average Subarray I
646	Maximum Length of Pair Chain
647	Palindromic Substrings
649	Dota2 Senate
653	Two Sum IV - Input is a BST
658	Find K Closest Elements
659	Split Array into Consecutive Subsequences
662	Maximum Width of Binary Tree
678	Valid Parenthesis String
680	Valid Palindrome II
682	Baseball Game
684	Redundant Connection
690	Employee Importance
692	Top K Frequent Words
694	Number of Distinct Islands
695	Max Area of Island
697	Degree of an Array
698	Partition to K Equal Sum Subsets
714	Best Time to Buy and Sell Stock with Transaction Fee
716	Max Stack
718	Maximum Length of Repeated Subarray
721	Accounts Merge
722	Remove Comments
724	Find Pivot Index
726	Number of Atoms
729	My Calendar I
730	Count Different Palindromic Subsequences
733	Flood Fill
735	Asteroid Collision
739	Daily Temperatures
740	Delete and Earn
747	Min Cost Climbing Stairs
761	Employee Free Time
765	Serialize and Deserialize N-ary Tree
768	Partition Labels
774	Maximum Depth of N-ary Tree
778	Reorganize String
782	Jewels and Stones
783	Search in a Binary Search Tree
785	Basic Calculator III
789	Kth Largest Element in a Stream
792	Binary Search
794	Swim in Rising Water
795	K-th Symbol in Grammar
797	Rabbits in Forest
800	Letter Case Permutation
801	Is Graph Bipartite?
803	Cheapest Flights Within K Stops
807	Custom Sort String
812	Rotate String
814	Smallest Rotation with Highest Score
816	Design HashSet
817	Design HashMap
826	Soup Servings
832	Binary Tree Pruning
843	Binary Trees With Factors
860	Design Circular Queue
861	Flipping an Image
866	Rectangle Overlap
874	Backspace String Compare
877	Shortest Path Visiting All Nodes
879	Maximize Distance to Closest Person
882	Peak Index in a Mountain Array
883	Car Fleet
886	Score of Parentheses
893	All Nodes Distance K in Binary Tree
898	Transpose Matrix
900	Reordered Power of 2
902	Minimum Number of Refueling Stops
907	Koko Eating Bananas
908	Middle of the Linked List
912	Random Pick with Weight
917	Boats to Save People
921	Spiral Matrix III
923	Super Egg Drop
926	Find and Replace Pattern
930	All Possible Full Binary Trees
931	Maximum Frequency Stack
940	Fruit Into Baskets
941	Sort Array By Parity
943	Sum of Subarray Minimums
945	Snakes and Ladders
948	Sort an Array
952	Word Subsets
957	Minimum Add to Make Parentheses Valid
972	Knight Dialer
975	Range Sum of BST
983	Validate Stack Sequences
985	Bag of Tokens
998	Check Completeness of a Binary Tree
1013	Fibonacci Number
1014	K Closest Points to Origin
1018	Largest Perimeter Triangle
1019	Squares of a Sorted Array
1021	Distribute Coins in Binary Tree
1023	Time Based Key-Value Store
1025	Minimum Cost For Tickets
1029	Vertical Order Traversal of a Binary Tree
1032	Satisfiability of Equality Equations
1034	Subarrays with K Different Integers
1036	Rotting Oranges
1038	Number of Squareful Arrays
1039	Find the Town Judge
1044	Find Common Characters
1054	Complement of Base 10 Integer
1055	Pairs of Songs With Total Durations Divisible by 60
1056	Capacity To Ship Packages Within D Days
1058	Lexicographically Smallest Equivalent String
1072	Next Greater Node In Linked List
1081	Video Stitching
1087	Longest Arithmetic Subsequence
1105	Uncrossed Lines
1106	Escape a Large Maze
1111	Minimum Score Triangulation of Polygon
1116	Maximum Level Sum of a Binary Tree
1122	Longest Duplicate Substring
1127	Last Stone Weight
1128	Remove All Adjacent Duplicates In String
1129	Longest String Chain
1138	Grumpy Bookstore Owner
1146	Greatest Common Divisor of Strings
1165	Meeting Scheduler
1171	Shortest Path in Binary Matrix
1184	Car Pooling
1185	Find in Mountain Array
1187	Print FooBar Alternately
1205	Defanging an IP Address
1212	Sequential Digits
1217	Relative Sort Array
1221	Element Appearing More Than 25% In Sorted Array
1224	Minimum Falling Path Sum II
1227	Number of Equivalent Domino Pairs
1236	N-th Tribonacci Number
1249	Snapshot Array
1250	Longest Common Subsequence
1254	Deepest Leaves Sum
1263	Number of Dice Rolls With Target Sum
1279	Prime Arrangements
1283	Reformat Date
1285	Balance a Binary Search Tree
1294	Range Frequency Queries
1319	Unique Number of Occurrences
1320	Remove All Adjacent Duplicates in String II
1331	Path with Maximum Gold
1340	The Dining Philosophers
1348	Maximum Score Of Spliced Array
1349	Check If It Is a Straight Line
1352	Maximum Profit in Job Scheduling
1356	Minimum Number of Moves to Make Palindrome
1397	Search Suggestions System
1400	Find Winner on a Tic Tac Toe Game
1406	Subtract the Product and Sum of Digits of an Integer
1407	Group the People Given the Group Size They Belong To
1408	Find the Smallest Divisor Given a Threshold
1414	Shortest Path in a Grid with Obstacles Elimination
1418	Fair Distribution of Cookies
1444	Number of Steps to Reduce a Number to Zero
1446	Angle Between Hands of a Clock
1461	Count All Valid Pickup and Delivery Options
1463	The K Weakest Rows in a Matrix
1476	Count Negative Numbers in a Sorted Matrix
1477	Product of the Last K Numbers
1478	Maximum Number of Events That Can Be Attended
1482	How Many Numbers Are Smaller Than the Current Number
1489	Pizza With 3n Slices
1492	Time Needed to Inform All Employees
1503	Reducing Dishes
1510	Find Lucky Integer in an Array
1528	Kids With the Greatest Number of Candies
1542	Consecutive Characters
1559	Cherry Pickup II
1567	Maximum Number of Vowels in a Substring of Given Length
1580	Shuffle the Array
1582	Design Browser History
1586	Longest Subarray of 1’s After Deleting One Element
1603	Running Sum of 1d Array
1630	Count Odd Numbers in an Interval Range
1635	Number of Good Pairs
1651	Shuffle String
1653	Number of Good Leaf Nodes Pairs
1669	Minimum Cost to Cut a Stick
1677	Matrix Diagonal Sum
1706	Min Cost to Connect All Points
1713	Dot Product of Two Sparse Vectors
1724	Customer Who Visited but Did Not Make Any Transactions
1738	Maximal Network Rank
1741	Sort Array by Increasing Frequency
1748	Best Team With No Conflicts
1761	Count Sorted Vowel Strings
1762	Furthest Building You Can Reach
1766	Minimum Number of Removals to Make Mountain Array
1776	Minimum Operations to Reduce X to Zero
1781	Check If Two String Arrays are Equivalent
1790	Lowest Common Ancestor of a Binary Tree III
1791	Richest Customer Wealth
1797	Goal Parser Interpretation
1798	Max Number of K-Sum Pairs
1801	Average Time of Process per Machine
1807	Partitioning Into Minimum Number Of Deci-Binary Numbers
1814	Jump Game VI
1829	Maximum Units on a Truck
1833	Find the Highest Altitude
1894	Merge Strings Alternately
1896	Maximum Score from Performing Multiplication Operations
1899	Count Items Matching a Rule
1900	Closest Dessert Cost
1908	Recyclable and Low Fat Products
1918	Maximum Score of a Good Subarray
1929	Maximum Value at a Given Index in a Bounded Array
1948	Rearrange Products Table
1966	Frequency of the Most Frequent Element
1983	Maximum Population Year
2020	Remove One Element to Make the Array Strictly Increasing
2024	Calculate Special Bonus
2028	The Earliest and Latest Rounds Where Players Compete
2042	Maximum Product Difference Between Two Pairs
2048	Build Array from Permutation
2058	Concatenation of Array
2095	Minimum Number of Swaps to Make the String Balanced
2101	Last Day Where You Can Still Cross
2118	Maximum Earnings From Taxi
2119	Minimum Number of Operations to Make Array Continuous
2133	Number of Pairs of Strings With Concatenation Equal to Target
2137	Final Value of Variable After Performing Operations
2152	The Number of Seniors and Juniors to Join the Company
2162	Partition Array Into Two Arrays to Minimize Sum Difference
2168	Check if Numbers Are Ascending in a Sentence
2199	Two Furthest Houses With Different Colors
2205	Find Good Days to Rob the Bank
2210	Find Target Indices After Sorting Array
2215	Finding 3-Digit Even Numbers
2219	Maximum Number of Words Found in Sentences
2221	Check if a Parentheses String Can Be Valid
2227	Sum of Subarray Ranges
2237	Longest Palindrome by Concatenating Two Letter Words
2265	Partition Array According to Given Pivot
2294	Minimum Time to Complete Trips
2337	Remove Digit From Number to Maximize Result
2368	Sum of Total Strength of Wizards
2383	Add Two Integers
2384	Root Equals Sum of Children
2428	Equal Row and Column Pairs
2472	Build a Matrix With Conditions
2482	Maximum Rows Covered by Columns
2491	Smallest Even Multiple
2502	Sort the People
2571	Find the Pivot Integer
2720	Minimize the Maximum Difference of Pairs
2732	Counter
2747	Apply Transform Over Each Element in Array
2808	Painting the Walls
2809	Create Hello World Function
2857	Total Distance Traveled
2858	Join Two Arrays by ID
3017	Number of Beautiful Integers in the Range
3062	Create a DataFrame from List