LeetCode

#	Title	Solutions	Time	Space	Difficulty	Tag	Notes
467	Unique Substrings in Wraparound String	Solution	O(n)	O(1)	Medium	DP
463	Island Perimeter	Solution	O(m*n)	O(1)	Easy
462	Minimum Moves to Equal Array Elements II	Solution	O(nlogn)	O(1)	Medium
459	Repeated Substring Pattern	Solution	O(n)	O(n)	Easy	KMP
456	132 Pattern	Solution	O(n)	O(n)	Medium	Stack
455	Assign Cookies	Solution	O(n)	O(1)	Easy
454	4Sum II	Solution	O(n)	O(n)	Medium	HashMap
453	Minimum Moves to Equal Array Elements	Solution	O(n)	O(1)	Easy
447	Number of Boomerangs	Solution	O(n^2)	O(n)	Easy	HashMap
441	Arranging Coins	Solution	O(n)	O(1)	Easy
438	Find All Anagrams in a String	Solution	O(n)	O(1)	Easy
436	Find Right Interval	Solution	O(nlogn)	O(n)	Medium	Binary Search
435	Non-overlapping Intervals	Solution	O(nlogn)	O(1)	Medium	Greedy
434	Number of Segments in a String	Solution	O(n)	O(1)	Easy
420	Strong Password Checker	Solution	?	?	Hard
419	Battleships in a Board	Solution	O(n^2)	O(1)	Medium	DFS
417	Pacific Atlantic Water Flow	Solution	O(mnMax(m,n))	O(m*n)	Medium	DFS
415	Add Strings	Solution	O(n)	O(1)	Easy
414	Third Maximum Number	Solution	O(n)	O(1)	Easy
413	Arithmetic Slices	Solution	O(n)	O(1)	Medium	DP
412	Fizz Buzz	Solution	O(n)	O(1)	Easy
404	Sum of Left Leaves	Solution	O(n)	O(h)	Easy
398	Random Pick Index	Solution			Medium	Reservoir Sampling
397	Integer Replacement	Solution	?	?	Easy	BFS
396	Rotate Function	Solution	O(n^2) could be optimized to O(n)	O(1)	Easy
390	Elimination Game	Solution	O(logn)	O(1)	Medium
389	Find the Difference	Solution	O(n)	O(1)	Easy
388	Longest Absolute File Path	Solution	O(n)	O(d)	Medium	Stack
387	First Unique Character in a String	Solution	O(n)	O(n)	Easy	HashMap
386	Lexicographical Numbers	Solution	O(n)	O(1)	Medium
379	Design Phone Directory	Solution	O(1)	O(n)	Medium
374	Guess Number Higher or Lower	Solution	O(logn)	O(1)	Easy	Binary Search
370	Range Addition	Solution	O(n+k)	O(1)	Medium
366	Find Leaves of Binary Tree	Solution	O(n)	O(h)	Medium	DFS
364	Nested List Weight Sum II	Solution	O(n)	O(h)	Medium	DFS
362	Design Hit Counter	Solution	O(1) amortized	O(k)	Medium	Design
359	Logger Rate Limiter	Solution	amortized O(1)	O(k)	Easy	HashMap
350	Intersection of Two Arrays II	Solution	O(m+n)	O((m+n)) could be optimized	Easy	HashMap, Binary Search
349	Intersection of Two Arrays	Solution	O(m+n)	O(min(m,n))	Easy	Two Pointers, Binary Search
346	Moving Average from Data Stream	Solution	O(1)	O(w))	Easy	Queue
339	Nested List Weight Sum	Solution	O(n)	O(h))	Easy	DFS
338	Counting Bits	Solution	O(nlogn)	O(h)	Medium
333	Largest BST Subtree	Solution	O(n)	O(n)	Medium
325	Maximum Size Subarray Sum Equals k	[Solution]	O(n)	O(n)	Medium	HashMap
314	Binary Tree Vertical Order Traversal	Solution	O(n)	O(n)	Medium	HashMap, BFS
311	Sparse Matrix Multiplication	Solution	O(mnl)	O(m*l)	Medium
301	Remove Invalid Parentheses	[Solution]	?	?	Hard	BFS
299	Bulls and Cows	Solution	O(n)	O(1)	Easy
295	Find Median from Data Stream	Solution	O(nlogn)	O(n)	Hard	Heap
293	Flip Game	Solution	?	O(n)	Easy
292	Nim Game	Solution	O(1)	O(1)	Easy
290	Word Pattern	Solution	O(n)	O(n)	Easy
289	Game of Life	Solution	O(m*n)	O(m*n), could be optimized to O(1)	Medium
288	Unique Word Abbreviation	Solution	O(n)	O(1)	Easy
285	Inorder Successor In BST	Solution	O(h)	O(1)	Medium
283	Move Zeroes	Solution	O(n)	O(1)	Easy
280	Wiggle Sort	Solution	O(n)	O(1)	Medium
278	First Bad Version	Solution	O(logn)	O(1)	Easy	Binary Search
276	Paint Fence	Solution	O(n)	O(1)	Easy	DP
273	Integer to English Words	[Solution]
270	Closest Binary Search Tree Value	Solution	O(h)	O(1)	Easy	DFS
266	Palindrome Permutation	Solution	O(n)	O(1)	Easy	HashMap
261	Graph Valid Tree	Solution	O(V+E)	O(V+E)	Medium
259	3Sum Smaller	Solution	O(n^2)	O(1)	Medium
258	Add Digits	Solution	O(1)	O(1)	Easy
257	Binary Tree Paths	Solution	O(n*h)	O(h)	DFS/Recursion
252	Meeting Rooms	Solution	O(nlogn)	O(1)
251	Flatten 2D Vector	Solution	O(1)	O(m*n)	Medium
250	Count Univalue Subtrees	Solution	O(n)	O(h)	Medium	DFS
249	Group Shifted Strings	Solution	O(nlogn)	O(n)
246	Strobogrammatic Number	Solution	O(n)	O(1)
243	Shortest Word Distance	Solution	O(n)	O(1)
237	Delete Node in a Linked List	Solution	O(1)	O(1)	Easy	LinkedList
226	Invert Binary Tree	Solution	O(n)	O(h)	Easy	DFS, recursion
223	Rectangle Area	Solution	O(1)	O(1)	Easy
219	Contains Duplicate II	Solution	O(n)	O(n)	Easy	HashMap
217	Contains Duplicate	Solution	O(n)	O(n)	Easy	HashSet
209	Minimum Size Subarray Sum	Solution	O(n)	O(1)	Medium
208	Implement Trie	Solution	O(n)	O(1)	Medium
206	Reverse Linked List	Solution	O(n)	O(1)	Easy
205	Isomorphic Strings	Solution	O(n)	O(1)	Easy
200	Number of Islands	Union Find DFS	O(m*n)	O(m*n)	Medium	Union Find, DFS
189	Rotate Array	Solution	O(n)	O(n), could be optimized to O(1)	Easy
182	Duplicate Emails	Solution	O(n^2)	O(n)	Easy
173	Binary Search Tree Iterator	Queue Stack	O(1)	O(h)	Medium
172	Factorial Trailing Zeroes	Solution	O(logn)	O(1)	Easy
170	Two Sum III - Data structure design	Solution	O(n)	O(n)	Easy
169	Majority Element	Solution	O(n)	O(1)	Easy
165	Compare Version Numbers	Solution	O(n)	O(1)	Easy
162	Find Peak Element	Solution	O(1)	O(logn)/O(n)	Binary Search
161	One Edit Distance	Solution	O(n)	O(1)
160	Intersection of Two Linked Lists	Solution	O(m+n)	O(1)	Easy	Linked List
157	Read N Characters Given Read4	Solution	O(n)	O(1)	Easy
155	Min Stack	Solution	O(1)	O(n)	Easy	Stack
151	Reverse Words in a String	Solution	O(n)	O(n)	Medium
142	Linked List Cycle II	Solution	O(n)	O(1)	Medium	Linked List
141	Linked List Cycle	Solution	O(n)	O(1)	Easy	Linked List
140	Word Break II	Solution	?	O(n^2)	Hard	Backtracking/DFS
139	Word Break	Solution	O(n^2)	O(n)	Medium	DP
133	Clone Graph	Solution	O(n)	O(n)	Medium	HashMap, BFS
125	Valid Palindrome	Solution	O(n)	O(1)	Easy	Two Pointers
122	Best Time to Buy and Sell Stock II	Solution	O(n)	O(1)	Medium	Greedy
121	Best Time to Buy and Sell Stock	Solution	O(n)	O(1)	Easy	DP
120	Triangle	Solution	O(m*n)	O(n)	Medium	DP
119	Pascal's Triangle II	Solution	O(n^2)	O(1)	Easy
118	Pascal's Triangle	Solution	O(n^2)	O(1)	Easy
117	Populating Next Right Pointers in Each Node II	Solution	O(n)	O(1)	Hard	BFS
116	Populating Next Right Pointers in Each Node	Solution	O(n)	O(1)	Medium	BFS
112	Path Sum	Solution	O(n)	O(1)	Easy	DFS
111	Minimum Depth of Binary Tree	Solution	O(n)	O(1)~O(h)	Easy	BFS, DFS
110	Balanced Binary Tree	Solution	O(n)	O(1)~O(h)	Easy	DFS
107	Binary Tree Level Order Traversal II	Solution	O(nlogn)	O(h)	Easy	BFS
103	Binary Tree Zigzag Level Order Traversal	Solution	O(n)	O(h)	Medium	BFS,DFS
102	Binary Tree Level Order Traversal	Solution	O(n)	O(h)	Easy	BFS
91	Decode Ways	Solution	O(n)	O(n)	Medium	DP
98	Validate Binary Search Tree	[Solution]	O(n)	O(1)	Medium	DFS/Recursion
79	Word Search	Solution	O(mnl) ?	O(m*n)	Medium	Backtracking/DFS
78	Subsets	Solution	O(n^2) ?	O(1)	Medium	Backtracking
76	Minimum Window Substring	Solution	O(n)	O(k)	Hard	Two Pointers
75	Sort Colors	Solution	O(n)	O(1)	Medium	Two Pointers
73	Set Matrix Zeroes	Solution	O(mn)	O(mn)	Medium
70	Climbing Stairs	Solution	O(n)	O(n)	Easy	DP
68	Text Justification	Solution	O(n)	O(1)	Hard
67	Add Binary	Solution	O(n)	O(1)	Easy
58	Length of Last Word	Solution	O(n)	O(1)	Easy
56	Merge Intervals	Solution	O(n*logn)	O(1)	Hard
47	Permutations II	Solution	O(n*n!)	O(n)	Medium	Backtracking
43	Multiply Strings	[Solution]			Medium
39	Combination Sum	Solution	O(k*n^k)	O(k)	Medium	Backtracking
38	Count and Say	Solution	O(n*2^n)	O(2^n)	Easy	Recursion, LinkedList
34	Search for a Range	Solution	O(logn)	O(1)	Medium	Array, Binary Search
31	Next Permutation	Solution	O(n)	O(1)	Medium	Array
24	Swap Nodes in Pairs	Solution	O(n)	O(1)	Easy	Recursion, LinkedList
23	Merge k Sorted Lists	Solution	O(n*logk)	O(logk)	Hard	Heap
22	Generate Parentheses	Solution	TBD	O(n)	Medium	Backtracking
21	Merge Two Sorted Lists	Solution	O(n)	O(1)	Easy
20	Valid Parentheses	Solution	O(n)	O(n)	Easy	Stack
17	Letter Combinations of a Phone Number	Solution	O(n*4^n)	O(n)	Medium	Backtracking
15	3Sum	Solution	O(n^2)	O(1)	Medium	Two Pointers
14	Longest Common Prefix	Solution	O(n*min(wordLength in this array))	O(1)	Easy
13	Roman to Integer	Solution	O(1)	O(1)	Easy
12	Integer to Roman	Solution	O(1)	O(1)	Medium
10	Regular Expression Matching	Solution	O(m*n)	O(m*n)	Hard	DP
9	Palindrome Number	Solution	O(logn)/(n)	O(1)	Easy
8	String to Integer (atoi)	Solution	O(n)	O(1)	Easy
7	Reverse Integer	Solution	O(1)	O(1)	Easy
6	ZigZag Conversion	Solution	O(n)	O(n)	Easy
3	Longest Substring Without Repeating Characters	Solution	O(n)	O(1)	Medium	HashMap, Sliding Window
2	Add Two Numbers	Solution	O(n)	O(1)	Medium	LinkedList
1	Two Sum	Solution	O(n)/O(n^2)	O(1)/O(n)	Easy	HashMap