zzghost / leetcode

Leetcode solution in Java

Arrays

No.	Title	Difficulty
001	Two Sums	Easy
011	Container With Most Water	Medium
015	3Sum	Medium
016	3Sum Closest	Medium
018	4Sum	Medium
026	Remove Duplicates from Sorted Array	Easy
027	Remove Element	Easy
031	Next Permutation	Medium
036	Valid Sudoku	Medium
039	Combination Sum	Medium
040	Combination Sum II	Medium
041	First Missing Positive	Hard
042	Trapping Rain Water	Hard
048	Rotate Image	Medium
054	Spiral Matrix	Medium
056	Merge Intervals	Medium
057	Insert Interval	Hard
059	Spiral Matrix II	Medium
062	Unique Paths	Easy
063	Unique Paths II	Medium
066	Plus One	Easy
073	Set Matrix Zeroes	Medium
074	Search a 2D Matrix	Medium
075	Sort Colors	Medium
079	Word Search	Medium
080	Remove Duplicates from Sorted Array II	Medium
081	Search in Rotated Sorted Array II	Medium
084	Largest Rectangle in Histogram	Hard
085	Maximal Rectangle	Hard
088	Merge Sorted Array	Easy
090	Subsets II	Medium
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium
118	Pascal's Triangle	Easy
119	Pascal's Triangle II	Easy
121	Best Time to Buy and Sell Stock	Easy
122	Best Time to Buy and Sell Stock II	Easy
123	Best Time to Buy and Sell Stock III	Hard
128	Longest Consecutive Sequence	Hard
152	Maximum Product Subarray	Medium
153	Find Minimum in Rotated Sorted Array	Medium
154	Find Minimum in Rotated Sorted Array II	Hard
167	Two Sum II - Input array is sorted	Easy
169	Majority Element	Easy
189	Rotate Array	Easy
209	Minimum Size Subarray Sum	Medium
216	Combination Sum III	Medium
217	Contains Duplicate	Easy
219	Contains Duplicate II	Easy
228	Summary Ranges	Medium
229	Majority Element II	Medium
238	Product of Array Except Self	Medium
268	Missing Number	Easy
283	Move Zeroes	Easy
287	Find the Duplicate Number	Medium
289	Game of Life	Medium
380	Insert Delete GetRandom O(1)	Medium
414	Third Maximum Number	Easy
442	Find All Duplicates in an Array	Medium
448	Find All Numbers Disappeared in an Array	Easy
485	Max Consecutive Ones	Easy
495	Teemo Attacking	Easy
532	K-diff Pairs in an Array	Easy
560	Subarray Sum Equals K	Medium
561	Array Partition I	Easy
565	Array Nesting	Medium
566	Reshape the Matrix	Easy
581	Shortest Unsorted Continuous Subarray	Easy
605	Can Place Flowers	Easy
611	Valid Triangle Number	Medium
621	Task Scheduler	Medium
628	Maximum Product of Three Numbers	Easy
643	Maximum Average Subarray I	Easy
661	Image Smoother	Easy
665	Non-decreasing Array	Easy
670	Maximum Swap	Medium
667	Beautiful Arrangement II	Medium
674	Longest Continuous Increasing Subsequence	Easy

String

No.	Title	Difficulty
003	Longest Substring Without Repeating Characters	Medium
006	ZigZag Conversion	Medium
013	Roman to Integer	Easy
020	Valid Parentheses	Easy
038	Count and Say	Easy
049	Group Anagrams	Medium
058	Length of Last Word	Easy
065	Valid Number	Hard
067	Add Binary	Easy
071	Simplify Path	Medium
125	Valid Palindrome	Easy
151	Reverse Words in a String	Medium
165	Compare Version Numbers	Medium
179	Largest Number	Medium
187	Repeated DNA Sequences	Medium
205	Isomorphic Strings	Easy
242	Valid Anagram	Easy
344	Reverse String	Easy
345	Reverse Vowels of a String	Easy
383	Ransom Note	Easy
415	Add Strings	Easy
438	Find All Anagrams in a String	Easy
520	Detect Capital	Easy
541	Reverse String II	Easy
551	Student Attendance Record I	Easy
557	Reverse Words in a String III	Easy
606	Construct String from Binary Tree	Easy
657	Judge Route Circle	Easy

Linked List

No.	Title	Difficulty
002	Add Two Numbers	Medium
019	Remove Nth Node From End of List	Medium
021	Merge Two Sorted Lists	Easy
023	Merge k Sorted Lists	Hard
024	Swap Nodes in Pairs	Medium
025	Reverse Nodes in k-Group	Hard
061	Rotate List	Medium
082	Remove Duplicates from Sorted List II	Medium
083	Remove Duplicates from Sorted List	Easy
086	Partition List	Medium
092	Reverse Linked List II	Medium
138	Copy List with Random Pointer	Medium
141	Linked List Cycle	Easy
142	Linked List Cycle II	Medium
143	Reorder List	Medium
160	Intersection of Two Linked Lists	Easy
203	Remove Linked List Elements	Easy
206	Reverse Linked List	Easy
234	Palindrome Linked List	Easy
237	Delete Node in a Linked List	Easy
445	Add Two Numbers II	Medium

Stack,Queue,Heap

No.	Title	Difficulty
150	Evaluate Reverse Polish Notation	Medium
155	Min Stack	Easy
215	Kth Largest Element in an Array	Medium
225	Implement Stack using Queues	Easy
232	Implement Queue using Stacks	Easy
295	Find Median from Data Stream	Hard

Tree

No.	Title	Difficulty
094	Binary Tree Inorder Traversal	Medium
098	Validate Binary Search Tree	Medium
100	Same Tree	Easy
101	Symmetric Tree	Easy
102	Binary Tree Level Order Traversal	Medium
103	Binary Tree Zigzag Level Order Traversal	Medium
104	Maximum Depth of Binary Tree	Easy
107	Binary Tree Level Order Traversal II	Easy
108	Convert Sorted Array to Binary Search Tree	Easy
109	Convert Sorted List to Binary Search Tree	Medium
110	Balanced Binary Tree	Easy
111	Minimum Depth of Binary Tree	Easy
112	Path Sum	Easy
113	Path Sum II	Medium
114	Flatten Binary Tree to Linked List	Medium
116	Populating Next Right Pointers in Each Node	Medium
117	Populating Next Right Pointers in Each Node II	Medium
129	Sum Root to Leaf Numbers	Medium
144	Binary Tree Preorder Traversal	Medium
145	Binary Tree Postorder Traversal	Hard
199	Binary Tree Right Side View	Medium
208	Implement Trie (Prefix Tree)	Medium
211	Add and Search Word - Data structure design	Medium
226	Invert Binary Tree	Easy
230	Kth Smallest Element in a BST｜Medium
235	Lowest Common Ancestor of a Binary Search Tree	Easy
236	Lowest Common Ancestor of a Binary Tree	Medium
257	Binary Tree Paths	Easy
307	Range Sum Query - Mutable	Medium
404	Sum of Left Leaves	Easy
437	Path Sum III	Easy
449	Serialize and Deserialize BST	Medium
450	Delete Node in a BST	Medium
538	Convert BST to Greater Tree	Easy
547	Friend Circles	Medium
687	Longest Univalue Path	Easy

Graph

No.	Title	Difficulty
127	Word Ladder	Medium
130	Surrounded Regions	Medium
200	Number of Islands	Medium
207	Course Schedule	Medium
210	Course Schedule II	Medium

Greedy

No.	Title	Difficulty
045	Jump Game II	Hard
055	Jump Game	Medium
134	Gas Station	Medium
376	Wiggle Subsequence	Medium
402	Remove K Digits	Medium
452	Minimum Number of Arrows to Burst Balloons	Medium
455	Assign Cookies	Easy

BackTracking

No.	Title	Difficulty
017	Letter Combinations of a Phone Number	Medium
022	Generate Parentheses	Medium
037	Sudoku Solver	Hard
046	Permutations	Medium
047	Permutations II	Medium
051	N-Queens	Hard
052	N-Queens II	Hard
077	Combinations	Medium
078	Subsets	Medium
093	Restore IP Addresses	Medium
473	Matchsticks to Square	Medium
526	Beautiful Arrangement	Medium
695	Max Area of Island	Easy

Dynamic Programming

No.	Title	Difficulty
053	Maximum Subarray	Easy
064	Minimum Path Sum	Medium
070	Climbing Stairs	Easy
072	Edit Distance	Hard
095	Unique Binary Search Trees II	Medium
096	Unique Binary Search Trees	Medium
120	Triangle	Medium
174	Dungeon Game	Hard
198	House Robber	Easy
213	House Robber II	Medium
221	Maximal Square	Medium
300	Longest Increasing Subsequence	Medium
322	Coin Change	Medium

Divide and Conquer

No.	Title	Difficulty
241	Different Ways to Add Parentheses	Medium
315	Count of Smaller Numbers After Self	Hard

Math

No.	Title	Difficulty
007	Reverse Integer	Easy
009	Palindrome Number	Easy.198. House Robber
012	Integer to Roman	Medium
136	Single Number	Easy
168	Excel Sheet Column Title	Easy
171	Excel Sheet Column Number	Easy
172	Factorial Trailing Zeroes	Easy
202	Happy Number	Easy
204	Count Primes	Easy
231	Power of Two	Easy
258	Add Digits	Easy

Binary Search

No.	Title	Difficulty	Comment
033	Search in Rotated Sorted Array	Medium
034	Search for a Range	Medium
035	Search Insert Position	Easy
050	Pow(x,n)	Medium	Divide and Conquer
069	Sqrt(x)	Easy
162	Find Peak Element	Medium
240	Search a 2D Matrix II	Medium
278	Find Bad Version	Easy
349	Intersection of Two Arrays	Easy
350	Intersection of Two Arrays II	Easy
367	Valid Perfect Square	Easy
374	Guess Number Higher or Lower	Easy
441	Arranging Coins	Easy

Other

No.	Title	Difficulty	Comment
137	Single Number II	Bit Manipulation
175	Combine Two Tables	Easy	SQL
176	Second Highest Salary	Easy	SQL
177	Nth Highest Salary	Easy	SQL
180	Consecutive Numbers	Medium	SQL
181	Employees Earning More Than Their Managers	Easy	SQL
182	Duplicate Emails	Easy	SQL
183	Customers Who Never Order	Easy	SQL
184	Department Highest Salary	Medium	SQL
190	Reverse Bits	Easy	Bit Manipulation
191	Number of 1 Bits	Easy	Bit Manipulation
192	Word Frequency	Medium	Bash
193	Valid Phone Numbers	Easy	Bash
194	Transpose File	Medium	Bash
195	Tenth Line	Easy	Bash
196	Delete Duplicate Emails	Easy	SQL
197	Rising Temperature	Easy	SQL
371	Sum of Two Integers	Easy	Bit Manipulation
595	Big Countries	Easy	SQL