LeetCode Problems (Sorted by #)

#	Title	Difficulty
1	Two Sum	Easy
2	Add Two Numbers	Medium
3	Longest Substring Without Repeating Characters	Medium
4	Median of Two Sorted Arrays	Hard
5	Longest Palindromic Substring	Medium
6	Zigzag Conversion	Medium
7	Reverse Integer	Easy
8	String to Integer (atoi)	Medium
9	Palindrome Number	Easy
11	Container With Most Water	Medium
12	Integer to Roman	Medium
13	Roman to Integer	Easy
14	Longest Common Prefix	Easy
15	3Sum	Medium
16	3Sum Closest	Medium
17	Letter Combinations of a Phone Number	Medium
18	4Sum	Medium
19	Remove Nth Node From End of List	Medium
20	Valid Parentheses	Easy
21	Merge Two Sorted Lists	Easy
22	Generate Parentheses	Medium
24	Swap Nodes in Pairs	Medium
26	Remove Duplicates from Sorted Array	Easy
27	Remove Element	Easy
28	Implement strStr()	Easy
29	Divide Two Integers	Medium
31	Next Permutation	Medium
33	Search in Rotated Sorted Array	Medium
34	Find First and Last Position of Element in Sorted Array	Medium
35	Search Insert Position	Easy
36	Valid Sudoku	Medium
38	Count and Say	Medium
39	Combination Sum	Medium
40	Combination Sum II	Medium
43	Multiply Strings	Medium
53	Maximum Subarray	Easy
57	Insert Interval	Medium
58	Length of Last Word	Easy
59	Spiral Matrix II	Medium
62	Unique Paths	Medium
66	Plus One	Easy
67	Add Binary	Easy
69	Sqrt(x)	Easy
70	Climbing Stairs	Easy
71	Simplify Path	Medium
73	Set Matrix Zeroes	Medium
74	Search a 2D Matrix	Medium
78	Subsets	Medium
83	Remove Duplicates from Sorted List	Easy
88	Merge Sorted Array	Easy
94	Binary Tree Inorder Traversal	Easy
98	Validate Binary Search Tree	Medium
100	Same Tree	Easy
101	Symmetric Tree	Easy
104	Maximum Depth of Binary Tree	Easy
108	Convert Sorted Array to Binary Search Tree	Easy
110	Balanced Binary Tree	Easy
111	Minimum Depth of Binary Tree	Easy
112	Path Sum	Easy
114	Flatten Binary Tree to Linked List	Medium
118	Pascal's Triangle	Easy
119	Pascal's Triangle II	Easy
122	Best Time to Buy and Sell Stock II	Medium
125	Valid Palindrome	Easy
130	Surrounded Regions	Medium
141	Linked List Cycle	Easy
142	Linked List Cycle II	Medium
151	Reverse Words in a String	Medium
157	Read N Characters Given Read4	Easy
160	Intersection of Two Linked Lists	Easy
163	Missing Ranges	Easy
167	Two Sum II - Input array is sorted	Easy
168	Excel Sheet Column Title	Easy
169	Majority Element	Easy
170	Two Sum III - Data structure design	Easy
171	Excel Sheet Column Number	Easy
176	Second Highest Salary	Easy
190	Reverse Bits	Easy
200	Number of Islands	Medium
202	Happy Number	Easy
205	Isomorphic Strings	Easy
206	Reverse Linked List	Easy
207	Course Schedule	Medium
210	Course Schedule II	Medium
215	Kth Largest Element in an Array	Medium
217	Contains Duplicate	Easy
219	Contains Duplicate II	Easy
225	Implement Stack using Queues	Easy
226	Invert Binary Tree	Easy
228	Summary Ranges	Easy
229	Majority Element II	Medium
230	Kth Smallest Element in a BST	Medium
231	Power of Two	Easy
238	Product of Array Except Self	Medium
242	Valid Anagram	Easy
246	Strobogrammatic Number	Easy
252	Meeting Rooms	Easy
253	Meeting Rooms II	Medium
257	Binary Tree Paths	Easy
258	Add Digits	Easy
266	Palindrome Permutation	Easy
270	Closest Binary Search Tree Value	Easy
285	Inorder Successor in BST	Medium
299	Bulls and Cows	Medium
308	Range Sum Query 2D - Mutable	Hard
332	Reconstruct Itinerary	Medium
340	Longest Substring with At Most K Distinct Characters	Medium
343	Integer Break	Medium
345	Reverse Vowels of a String	Easy
346	Moving Average from Data Stream	Easy
347	Top K Frequent Elements	Medium
349	Intersection of Two Arrays	Easy
350	Intersection of Two Arrays II	Easy
353	Design Snake Game	Medium
359	Logger Rate Limiter	Easy
378	Kth Smallest Element in a Sorted Matrix	Medium
388	Longest Absolute File Path	Medium
399	Evaluate Division	Medium
404	Sum of Left Leaves	Easy
408	Valid Word Abbreviation	Easy
412	Fizz Buzz.py	Easy
415	Add Strings	Easy
418	Sentence Screen Fitting	Medium
450	Delete Node in a BST	Medium
455	Assign Cookies	Easy
482	License Key Formatting	Easy
500	Keyboard Row	Easy
501	Find Mode in Binary Search Tree	Easy
504	Base 7	Easy
506	Relative Ranks	Easy
509	Fibonacci Number	Easy
520	Detect Capital	Easy
531	Lonely Pixel I	Medium
536	Construct Binary Tree from String	Medium
547	Number of Provinces	Medium
551	Student Attendance Record I	Easy
560	Subarray Sum Equals K	Medium
575	Distribute Candies	Easy
598	Range Addition II	Easy
617	Merge Two Binary Trees	Easy
621	Task Scheduler	Medium
634	Find the Derangement of An Array	Medium
674	Longest Continuous Increasing Subsequence	Easy
680	Valid Palindrome II	Easy
681	Next Closest Time	Medium
683	K Empty Slots	Hard
686	Repeated String Match	Medium
690	Employee Importance	Easy
695	Max Area of Island	Medium
696	Count Binary Substrings	Easy
701	Insert into a Binary Search Tree	Medium
703	Kth Largest Element in a Stream	Easy
706	Design HashMap	Easy
724	Find Pivot Index	Easy
735	Asteroid Collision	Medium
744	Find Smallest Letter Greater Than Target	Easy
747	Largest Number At Least Twice of Others	Easy
755	Pour Water	Medium
784	Letter Case Permutation	Medium
788	Rotated Digits	Easy
792	Number of Matching Subsequences	Medium
796	Rotate String	Easy
804	Unique Morse Code Words	Easy
821	Shortest Distance to a Character	Easy
836	Rectangle Overlap	Easy
843	Guess the Word	Hard
848	Shifting Letters	Medium
852	Peak Index in a Mountain Array	Easy
853	Car Fleet	Medium
860	Lemonade Change	Easy
867	Transpose Matrix	Easy
876	Middle of the Linked List	Easy
904	Fruit Into Baskets	Medium
917	Reverse Only Letters	Medium
929	Unique Email Addresses	Easy
937	Reorder Data in Log Files	Easy
938	Range Sum of BST	Easy
997	Find the Town Judge	Easy
1002	Find Common Characters	Easy
1005	Maximize Sum Of Array After K Negations	Easy
1007	Minimum Domino Rotations For Equal Row	Medium
1021	Remove Outermost Parentheses	Easy
1048	Longest String Chain	Medium
1057	Campus Bikes	Medium
1058	Minimize Rounding Error to Meet Target	Medium
1064	Fixed Point	Easy
1086	High Five	Easy
1110	Delete Nodes And Return Forest	Medium
1114	Print in Order	Easy
1118	Number of Days in a Month	Easy
1119	Remove Vowels from a String	Easy
1136	Parallel Courses	Medium
1162	As Far from Land as Possible	Medium
1170	Compare Strings by Frequency of the Smallest Character	Easy
1184	Distance Between Bus Stops	Easy
1189	Maximum Number of Balloons	Easy
1217	Minimum Cost to Move Chips to The Same Position	Easy
1237	Find Positive Integer Solution for a Given Equation	Easy
1313	Decompress Run-Length Encoded List	Easy
1344	Angle Between Hands of a Clock	Medium
1346	Check If N and Its Double Exist	Easy
1351	Count Negative Numbers in a Sorted Matrix	Easy
1356	Sort Integers by The Number of 1 Bits	Easy
1385	Find the Distance Value Between Two Arrays	Easy
1394	Find Lucky Integer in an Array	Easy
1417	Reformat The String	Easy
1423	Maximum Points You Can Obtain from Cards	Medium
1448	Count Good Nodes in Binary Tree	Medium
1456	Maximum Number of Vowels in a Substring of Given Length	Easy
1464	Maximum Product of Two Elements in an Array	Easy
1469	Find All The Lonely Nodes	Easy
1470	Shuffle the Array	Easy
1475	Final Prices With a Special Discount in a Shop	Easy
1491	Average Salary Excluding the Minimum and Maximum Salary	Easy
1493	Longest Subarray of 1's After Deleting One Element	Medium
1507	Reformat Date	Easy
1509	Minimum Difference Between Largest and Smallest Value in Three Moves	Medium
1525	Number of Good Ways to Split a String	Medium
1576	Replace All ?'s to Avoid Consecutive Repeating Characters	Easy
1592	Rearrange Spaces Between Words	Easy
1603	Design Parking System	Easy
1610	Maximum Number of Visible Points	Hard
1631	Path With Minimum Effort	Medium
1725	Number Of Rectangles That Can Form The Largest Square	Easy
1732	Find the Highest Altitude	Easy
1768	Merge Strings Alternately	Easy
1773	Count Items Matching a Rule	Easy
1776	Car Fleet II	Hard
1791	Find Center of Star Graph	Easy
1796	Second Largest Digit in a String	Easy
1800	Maximum Ascending Subarray Sum	Easy
1812	Determine Color of a Chessboard Square	Easy
1822	Sign of the Product of an Array	Easy
1844	Replace All Digits with Characters	Easy
1863	Sum of All Subset XOR Totals	Easy
1876	Substrings of Size Three with Distinct Characters	Easy
1893	Check if All the Integers in a Range Are Covered	Easy
1913	Maximum Product Difference Between Two Pairs	Easy
1920	Build Array from Permutation	Easy
1945	Sum of Digits of String After Convert	Easy
1957	Delete Characters to Make Fancy String	Easy
1961	Check If String Is a Prefix of Array	Easy
2000	Reverse Prefix of Word	Easy
2006	Count Number of Pairs With Absolute Difference K	Easy
2011	Final Value of Variable After Performing Operations	Easy
2016	Maximum Difference Between Increasing Elements	Easy
2027	Minimum Moves to Convert String	Easy
2042	Check if Numbers Are Ascending in a Sentence	Easy
2048	Next Greater Numerically Balanced Number	Medium

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LeetCode Problems (Categorized by Difficulty)

Easy

#	Title
1	Two Sum
7	Reverse Integer
9	Palindrome Number
13	Roman to Integer
14	Longest Common Prefix
20	Valid Parentheses
21	Merge Two Sorted Lists
26	Remove Duplicates from Sorted Array
27	Remove Element
28	Implement strStr()
35	Search Insert Position
53	Maximum Subarray
58	Length of Last Word
66	Plus One
67	Add Binary
69	Sqrt(x)
70	Climbing Stairs
83	Remove Duplicates from Sorted List
88	Merge Sorted Array
94	Binary Tree Inorder Traversal
100	Same Tree
101	Symmetric Tree
104	Maximum Depth of Binary Tree
108	Convert Sorted Array to Binary Search Tree
110	Balanced Binary Tree
111	Minimum Depth of Binary Tree
112	Path Sum
118	Pascal's Triangle
119	Pascal's Triangle II
125	Valid Palindrome
141	Linked List Cycle
157	Read N Characters Given Read4
160	Intersection of Two Linked Lists
163	Missing Ranges
167	Two Sum II - Input array is sorted
168	Excel Sheet Column Title
169	Majority Element
170	Two Sum III - Data structure design
171	Excel Sheet Column Number
176	Second Highest Salary
190	Reverse Bits
202	Happy Number
205	Isomorphic Strings
206	Reverse Linked List
217	Contains Duplicate
219	Contains Duplicate II
225	Implement Stack using Queues
226	Invert Binary Tree
228	Summary Ranges
231	Power of Two
242	Valid Anagram
246	Strobogrammatic Number
252	Meeting Rooms
257	Binary Tree Paths
258	Add Digits
266	Palindrome Permutation
270	Closest Binary Search Tree Value
343	Integer Break
345	Reverse Vowels of a String
346	Moving Average from Data Stream
349	Intersection of Two Arrays
350	Intersection of Two Arrays II
359	Logger Rate Limiter
404	Sum of Left Leaves
408	Valid Word Abbreviation
412	Fizz Buzz.py
415	Add Strings
455	Assign Cookies
482	License Key Formatting
500	Keyboard Row
501	Find Mode in Binary Search Tree
504	Base 7
506	Relative Ranks
509	Fibonacci Number
520	Detect Capital
551	Student Attendance Record I
575	Distribute Candies
598	Range Addition II
617	Merge Two Binary Trees
621	Task Scheduler
674	Longest Continuous Increasing Subsequence
680	Valid Palindrome II
690	Employee Importance
696	Count Binary Substrings
703	Kth Largest Element in a Stream
706	Design HashMap
724	Find Pivot Index
744	Find Smallest Letter Greater Than Target
747	Largest Number At Least Twice of Others
788	Rotated Digits
796	Rotate String
804	Unique Morse Code Words
821	Shortest Distance to a Character
836	Rectangle Overlap
852	Peak Index in a Mountain Array
860	Lemonade Change
867	Transpose Matrix
876	Middle of the Linked List
929	Unique Email Addresses
937	Reorder Data in Log Files
938	Range Sum of BST
997	Find the Town Judge
1002	Find Common Characters
1005	Maximize Sum Of Array After K Negations
1021	Remove Outermost Parentheses
1064	Fixed Point
1086	High Five
1114	Print in Order
1118	Number of Days in a Month
1119	Remove Vowels from a String
1170	Compare Strings by Frequency of the Smallest Character
1184	Distance Between Bus Stops
1189	Maximum Number of Balloons
1217	Minimum Cost to Move Chips to The Same Position
1237	Find Positive Integer Solution for a Given Equation
1313	Decompress Run-Length Encoded List
1346	Check If N and Its Double Exist
1351	Count Negative Numbers in a Sorted Matrix
1356	Sort Integers by The Number of 1 Bits
1385	Find the Distance Value Between Two Arrays
1394	Find Lucky Integer in an Array
1417	Reformat The String
1456	Maximum Number of Vowels in a Substring of Given Length
1464	Maximum Product of Two Elements in an Array
1469	Find All The Lonely Nodes
1470	Shuffle the Array
1475	Final Prices With a Special Discount in a Shop
1491	Average Salary Excluding the Minimum and Maximum Salary
1507	Reformat Date
1576	Replace All ?'s to Avoid Consecutive Repeating Characters
1592	Rearrange Spaces Between Words
1603	Design Parking System
1725	Number Of Rectangles That Can Form The Largest Square
1732	Find the Highest Altitude
1768	Merge Strings Alternately
1773	Count Items Matching a Rule
1791	Find Center of Star Graph
1796	Second Largest Digit in a String
1800	Maximum Ascending Subarray Sum
1812	Determine Color of a Chessboard Square
1822	Sign of the Product of an Array
1844	Replace All Digits with Characters
1863	Sum of All Subset XOR Totals
1876	Substrings of Size Three with Distinct Characters
1893	Check if All the Integers in a Range Are Covered
1913	Maximum Product Difference Between Two Pairs
1920	Build Array from Permutation
1945	Sum of Digits of String After Convert
1957	Delete Characters to Make Fancy String
1961	Check If String Is a Prefix of Array
2000	Reverse Prefix of Word
2006	Count Number of Pairs With Absolute Difference K
2011	Final Value of Variable After Performing Operations
2016	Maximum Difference Between Increasing Elements
2027	Minimum Moves to Convert String
2042	Check if Numbers Are Ascending in a Sentence

Medium

#	Title
2	Add Two Numbers
3	Longest Substring Without Repeating Characters
5	Longest Palindromic Substring
6	Zigzag Conversion
8	String to Integer (atoi)
11	Container With Most Water
12	Integer to Roman
15	3Sum
16	3Sum Closest
17	Letter Combinations of a Phone Number
18	4Sum
19	Remove Nth Node From End of List
22	Generate Parentheses
24	Swap Nodes in Pairs
29	Divide Two Integers
31	Next Permutation
33	Search in Rotated Sorted Array
34	Find First and Last Position of Element in Sorted Array
36	Valid Sudoku
38	Count and Say
39	Combination Sum
40	Combination Sum II
43	Multiply Strings
57	Insert Interval
59	Spiral Matrix II
62	Unique Paths
71	Simplify Path
73	Set Matrix Zeroes
74	Search a 2D Matrix
78	Subsets
98	Validate Binary Search Tree
114	Flatten Binary Tree to Linked List
122	Best Time to Buy and Sell Stock II
130	Surrounded Regions
142	Linked List Cycle II
151	Reverse Words in a String
200	Number of Islands
207	Course Schedule
210	Course Schedule II
215	Kth Largest Element in an Array
229	Majority Element II
230	Kth Smallest Element in a BST
238	Product of Array Except Self
253	Meeting Rooms II
285	Inorder Successor in BST
299	Bulls and Cows
332	Reconstruct Itinerary
340	Longest Substring with At Most K Distinct Characters
347	Top K Frequent Elements
353	Design Snake Game
378	Kth Smallest Element in a Sorted Matrix
388	Longest Absolute File Path
399	Evaluate Division
418	Sentence Screen Fitting
450	Delete Node in a BST
531	Lonely Pixel I
536	Construct Binary Tree from String
547	Number of Provinces
560	Subarray Sum Equals K
634	Find the Derangement of An Array
681	Next Closest Time
686	Repeated String Match
695	Max Area of Island
701	Insert into a Binary Search Tree
735	Asteroid Collision
755	Pour Water
784	Letter Case Permutation
792	Number of Matching Subsequences
848	Shifting Letters
853	Car Fleet
904	Fruit Into Baskets
917	Reverse Only Letters
1007	Minimum Domino Rotations For Equal Row
1048	Longest String Chain
1057	Campus Bikes
1058	Minimize Rounding Error to Meet Target
1110	Delete Nodes And Return Forest
1136	Parallel Courses
1162	As Far from Land as Possible
1344	Angle Between Hands of a Clock
1423	Maximum Points You Can Obtain from Cards
1448	Count Good Nodes in Binary Tree
1493	Longest Subarray of 1's After Deleting One Element
1509	Minimum Difference Between Largest and Smallest Value in Three Moves
1525	Number of Good Ways to Split a String
1631	Path With Minimum Effort
2048	Next Greater Numerically Balanced Number

Hard

#	Title
4	Median of Two Sorted Arrays
308	Range Sum Query 2D - Mutable
683	K Empty Slots
843	Guess the Word
1610	Maximum Number of Visible Points
1776	Car Fleet II