LeetCode

No.	#	Title	Solution	Difficulty	Solved Date	Tag	Review Date
1	461	Hamming Distance	Java	Easy	2017.1.6	Math, Bit manipulation	2018.1.19 2018.6.19
2	412	Fizz Buzz	Python Java	Easy	2017.1.7	String	2018.1.14 2018.6.19
3	344	Reverse String	Java	Easy	2017.1.7	Two Pointers, String	2018.1.8 2018.6.19
4	463	Island Perimeter	Python	Easy	2017.1.8	Array	2018.1.19 2018.6.19 2018.10.10 2018.10.27 2018.11.12
5	448	Find All Numbers Disappeared in an array	Java	Easy	2017.1.8	Array	2018.1.10 2018.5.14 2018.6.20
6	136	Single Number	Python, Java	Easy	2017.1.10	Hash Table, Bit Manipulation	2018.5.4 2018.6.19 2018.10.10 2018.10.19 2018.10.30
7	371	Sum of Two Integers	Java	Easy	2017.1.10	Bit Manipulation	2018.10.11
8	389	Find the difference	Java	Easy	2017.1.11	Hash Table, Bit Manipulation	2018.5.18
9	476	Number Complement	Python	Easy	2017.1.12
10	455	Assign-cookies	Python	Easy	2017.1.16
11	453	Minimum Moves to Equal Array Elements	Java	Easy	2017.1.18	Math	2018.1.11
12	118	Pascal's Triangle	Java	Easy	2017.2.20	Array	2018.1.6
13	21	Merge Two Sorted Lists	Java	Easy	2017.2.20	Linked List	2017.12.15 2018.1.5 2018.2.10 2018.4.12 2018.7.7 2018.10.12 2018.10.19
14	1	Two Sum	Java	Easy	2017.3.9	Array, Hash Table	2017.12.13 2018.2.1 2018.2.25 2018.3.25 2018.3.28 2018.4.10 2018.4.16 2018.4.24 2018.5.29 2018.10.14
15	7	Reverse Integer	Java	Easy	2017.3.9	Math	2018.10.16
16	9	Palindrome Number	Java	Easy	2017.3.9
17	14	Longest Common Prefix	Java	Easy	2017.3.9	String	2017.12.24 2018.10.16 2018.10.26
18	20	Valid Parentheses	Java	Easy	2017.3.9	Stack	2018.4.23 2018.10.27 2018.11.12
19	26	Remove Duplicates from Sorted Array	Java	Easy	2017.3.10	Linked List	2018.2.11 2018.4.24 2018.6.22 2018.10.14 2018.10.15
20	27	Remove Element	Java	Easy	2017.3.10
21	28	Implement strStr()	Java	Easy	2017.3.15	String	2018.3.17
22	35	Search Insert Position	Java	Easy	2017.3.15
23	38	Count and Say	Java	Easy	2017.3.16	String	2018.10.15
24	53	Maximum Subarray	Java	Easy	2017.3.16	Array, Divide and Conquer,Dynamic Programming	2017.12.17 2018.1.23 2018.1.27 2018.2.21 2018.4.17 2018.4.18 2018.5.24 2018.7.10 2018.9.14 2018.9.28 2018.10.14 2018.10.27 2018.11.8
25	58	Length of Last Word	Java	Easy	2017.3.16
26	66	Plus One	Java	Easy	2017.3.17	Math. Array	2017.12.14 2018.10.14
27	67	Add Binary	Java	Easy	2017.3.17	Math, String	2017.12.13 2018.10.15 2018.10.26 2018.11.10
28	69	Sqrt(x)	Java	Easy	2017.3.17		2018.3.22 2018.11.7
29	88	Merge Sorted Array	Java	Easy	2017.3.21	Array, Two Pointer	2018.4.24 2018.10.16 2018.11.11
30	101	Symmetric Tree	Java	Easy	2017.3.21	Tree	2018.1.1 2018.3.15 2018.4.19 2018.5.29 2018.7.9 2018.10.14
31	119	Pascal's Triangle Ⅱ	Java	Easy	2017.3.22
32	121	Best Time to Buy and Sell Stock	Java	Easy	2017.3.23	Array, Dynamic Programming	2017.12.17 2018.1.28 2018.2.21 2018.2.26 2018.4.13 2018.4.17 2018.5.24 2018.7.6 2018.10.12 2019.1.10 2019.2.12
33	122	Best Time to Buy and Sell Stock Ⅱ	Java	Easy	2017.3.23	Array, Greedy	2017.12.18 2018.2.26 2018.10.11 2019.2.12
34	167	Two Sum Ⅱ - Input array is sorted	Java	Easy	2017.3.24	Array, Two Pointers, Binary Search	2017.12.13 2018.4.10 2018.4.28
35	414	Third Maximum Number	Java	Easy	2017.3.27	Array	2017.11.3 2018.1.8
36	268	Missing Number	Java	Easy	2017.3.27		2018.6.30
37	485	Max Consecutive Ones	Java	Easy	2017.3.28	Array	2018.10.27
38	219	Contains Duplicate Ⅱ	Java	Easy	2017.3.28	Array, HashMap	2018.2.14 2018.11.3
39	500	Keyboard Row	Java	Easy	2017.4.1
40	349	Intersection of Two Arrays	Java	Easy	2017.4.1	Array	2018.10.11 2018.11.11
41	409	Longest Palindrome	Java	Easy	2017.4.7	HashTable	2018.3.19
42	350	Intersection of Two Arrays Ⅱ	Java	Easy	2017.4.7	Two Pointers, HashMap	2018.10.12 2018.11.11
43	141	Linked List Cycle	Java	Easy	2017.5.25	Linked List, Two Pointers	2017.12.15 2018.1.24 2018.2.10 2018.4.10 2018.4.24 2018.10.15 2018.10.18 2019.2.10
44	142	Linked List Cycle Ⅱ	Java	Medium	2017.5.25	Linked List, Two Pointers	2017.12.25 2018.2.10 2018.4.24 2018.10.18
45	160	Intersection of Two Linked Lists	Java	Easy	2017.5.25	Linked List	2017.12.23 2018.1.9 2018.2.10 2018.4.10 2018.4.17 2018.10.16
46	234	Palindrome Linked List	Java	Easy	2017.5.26	Linked List, Two Pointers	2017.12.23 2018.1.24 2018.2.11 2018.4.13
47	203	Remove Linked List Elements	Java	Easy	2017.5.27	Linked List	2017.12.26 2018.2.11
48	2	Add Two Numbers	Java	Medium	2017.5.27	Linked List, Math	2017.12.13 2018.1.26 2018.2.11 2018.4.17 2018.9.21 2018.10.21
49	445	Add Two Numbers Ⅱ	Java	Medium	2017.5.30	Linked List	2017.12.13 2018.1.26 2018.2.12 2018.4.23
50	24	Swap Nodes in Pairs	Java	Medium	2017.6.2	Linked List	2017.12.25 2018.9.27
51	19	Remove Nth Node From End of List	Java	Medium	2017.6.2	Linked List	2017.12.25 2018.9.24 2018.10.18
52	147	Insertion Sort List	Java	Medium	2017.6.7	Linked List, Sort
53	86	Partition List	Java	Medium	2017.6.7	Linked List, Two Pointers	2018.1.25 2018.10.3
54	92	Reverse Linked List Ⅱ	Java	Medium	2017.6.8	Linked List	2018.2.12
55	82	Remove Duplicates from Sorted List Ⅱ	Java	Medium	2017.6.8	Linked List	2018.10.2
56	61	Rotate List	Java	Medium	2017.6.9	Linked List, Two Pointers	2018.2.12 2018.10.2
57	25	Reverse Nodes in k-Group	Java	Hard	2017.6.10	Linked List	2018.11.17
58	148	Sort List	Java	Medium	2017.6.11	Linked List, Sort	2017.12.15 2018.2.13
59	237	Delete Node in a Linked List	Java	Easy	2017.6.14	Linked List	2017.12.14 2018.2.10 2018.6.30
60	206	Reverse Linked List	Java	Easy	2017.6.14	Linked List	2017.12.15 2018.1.17 2018.2.8 2018.2.10 2018.3.11 2018.4.10 2018.6.30 2018.9.28 2018.10.11
61	328	Odd Even Linked List	Java	Medium	2017.6.15	Linked List	2017.12.16 2018.2.11
62	83	Remove Duplicates from Sorted List	Java	Easy	2017.6.15	Linked List	2017.12.26
63	109	Convert Sorted List to Binary Search Tree	Java	Medium	2017.6.17	Linked List, DFS	2018.2.12
64	496	Next Greater Element I	Java	Easy	2017.6.19	Stack, HashMap	2018.1.12
65	503	Next Greater Element II	Java	Medium	2017.6.19	Stack	2018.1.13
66	94	Binary Tree Inorder Travelsal	Java	Medium	2017.6.20	Stack	2018.1.4 2018.2.13 2018.3.15 2018.4.3 2018.4.24 2018.5.8 2018.6.8 2018.10.3
67	144	Binary Tree Preorder Travelsal	Java	Medium	2017.6.22	Stack	2018.1.4 2018.2.13 2018.3.15 2018.4.24 2018.9.28
68	145	Binary Tree Postorder Travelsal	Java	Hard	2017.6.22	Stack	2018.1.4 2018.2.13 2018.3.15 2018.4.24 2018.10.24
69	394	Decode String	Java	Medium	2017.6.27	Stack	2018.1.9
70	341	Flatten Nested List Iterator	Java	Medium	2017.6.27	Design, Stack	2018.1.8 2018.1.28 2018.10.26
71	173	Binary Search Tree Iterator	Java	Medium	2017.6.27	Stack	2017.12.31 2018.1.7 2018.3.5 2018.4.18 2018.10.23
72	155	Min Stack	Java	Easy	2017.7.4	Stack	2018.3.7 2018.4.11
73	225	Implement Stack using Queues	Java	Easy	2017.7.5	Stack	2018.2.27
74	232	Implement Queue using Stacks	Java	Easy	2017.7.5	Queue	2018.2.27 2018.4.23 2018.7.19
75	331	Verify Preorder Serialization of a Binary Tree	Java	Medium	2017.7.6	Stack
76	561	Array Partition I	Java	Easy	2017.7.10	Array	2018.6.25
77	189	Rotate Array	Java	Easy	2017.7.10	Array	2017.12.10 2018.4.10 2018.6.9 2018.10.27
78	605	Can Place Flowers	Java	Easy	2017.7.10	Array
79	581	Shortest Unsorted Continuous Subarray	Java	Easy	2017.7.11	Array
80	566	Reshape the Matrix	Java	Easy	2017.7.11	Array
81	628	Maximum Product of Three Numbers	Java	Easy	2017.7.13	Array	2018.1.18
82	105	Construct Binary Tree from Preorder and Inorder Traversal	Java	Medium	2017.7.14	Array	2017.7.16 2018.1.5 2018.2.13 2018.3.21
83	106	Construct Binary Tree from Inorder and Postorder Traversal	Java	Medium	2017.7.15	Array	2017.7.16 2018.1.5 2018.2.13 2018.3.21 2018.10.14 2018.10.24
84	532	K-diff Pairs in an Array	Java	Easy	2017.7.15	Array	2017.7.16 2018.1.8 2018.1.15
85	521	Longest Uncommon Subsequence I	Java	Easy	2017.7.15	String	2017.7.16
86	606	Construct String from Binary Tree	Java	Easy	2017.7.15	String
87	125	Valid Palindrome	Java	Easy	2017.7.15	String	2017.7.17 2018.1.6 2018.3.17 2018.4.24 2018.10.16 2018.10.27 2018.11.11
88	520	Detect Capital	Java	Easy	2017.7.15	String	2017.7.17 2018.1.10
89	383	Ransom Note	Java	Easy	2017.7.15	String	2018.9.4
90	551	Student Attendance Record I	Java	Easy	2017.7.15	String
91	557	Reverse Words in a String III	Java	Easy	2017.7.18	String	2018.1.19
92	541	Reverse String II	Java	Easy	2017.7.19	String	2018.1.8
93	459	Repeated Substring Pattern	Java	Easy	2017.7.19	String	2018.1.15
94	434	Number of Segments in a String	Java	Easy	2017.7.19	String	2018.1.16
95	345	Reverse Vowels of a String	Java	Easy	2017.7.20	String	2018.1.16
96	643	Maximum Average Subarray I	Java	Easy	2017.7.20	Array	2018.1.17
97	594	Longest Harmonious Subsequence	Java	Easy	2017.7.20	HashTable	2018.1.20
98	575	Distribute Candies	Java	Easy	2017.7.20	HashTable	2018.1.16
99	447	Number of Boomerangs	Java	Easy	2017.7.20	HashTable	2018.1.20
100	438	Find All Anagrams in a String	Java	Easy	2017.7.21	HashMap	2018.1.22 2018.10.10 2018.10.15 2018.10.27 2018.11.10
101	599	Minimum Index Sum of Two Lists	Java	Easy	2017.7.21	HashMap	2018.1.17
102	205	Isomorphic Strings	Java	Easy	2017.7.23	Hash Table	2018.1.7 2019.2.4
103	645	Set Mismatch	Java	Easy	2017.7.23	HashMap, Array	2018.1.14
104	204	Count Primes	Java	Easy	2017.7.24	HashMap, Math	2018.1.7 2018.3.18
105	290	Word Pattern	Java	Easy	2017.7.24	HashTable	2018.1.7 2018.5.25
106	12	Integer to Roman	Java	Medium	2017.7.27	Math, String	2018.1.4 2018.3.7 2018.9.23 2018.10.28
107	13	Roman to Integer	Java	Easy	2017.7.27	Math, String	2018.1.4 2018.3.7 2018.6.30 2018.10.11 2018.10.28
108	111	Minimum Depth of Binary Tree	Java	Easy	2017.7.27	Tree, DFS, BFS	2018.1.4 2018.5.29 2018.10.15
109	617	Merge Two Binary Trees	Java	Easy	2017.7.31	Tree	2017.12.30 2018.1.14 2018.2.5 2018.4.9 2018.6.8
110	70	Climbing Stairs	Java	Easy	2017.8.2	Dynamic Programming	2017.12.17 2018.1.5 2018.2.21 2018.3.10 2018.4.17 2018.5.24
111	100	Same Tree	Java	Easy	2017.8.4	Tree, DFS	2017.12.30 2018.1.5 2018.2.19 2018.4.3
112	169	Majority Element	Java	Easy	2017.8.6	Array, Divide and Conquer, Bit Manipulation	2018.1.6 2018.2.6 2018.3.2 2018.7.19
113	171	Excel Sheet Column Number	Java	Easy	2017.8.6	Math	2018.1.7 2018.6.30 2018.10.28
114	690	Employee Importance	Java	Easy	2017.10.11	DFS	2018.5.28
115	695	Max Area of Island	Java	Easy	2017.10.12	DFS	2018.1.18
116	693	Binary Number with Alternating Bits	Java	Easy	2017.10.12	Bit Manipulation
117	347	Top K Frequent Element	Java	Medium	2017.10.14	Hash Table, Heap	2017.12.16 2018.2.22 2018.2.26 2018.4.24 2018.9.5 2018.10.14 2018.10.23
118	692	Top K Frequent Words	Java	Medium	2017.10.14	Hash Table, Heap	2018.10.23
119	657	Judge Route Circle	Java	Easy	2017.10.17	String	2018.8.16
120	303	Range Sum Query - Immutable	Java	Easy	2017.10.18	Dynamic Programming	2017.12.19 2018.1.29 2018.2.22 2018.11.11
121	387	First Unique Character in a String	Java	Easy	2017.10.19	String	2018.2.14 2018.4.13 2018.4.15 2018.6.30 2018.10.11
122	108	Convert Sorted Array to Binary Search Tree	Java	Easy	2017.10.19	Tree, DFS	2018.1.1
123	198	House Robber	Java	Easy	2017.10.19	Dynamic Programming	2017.12.5 2017.12.18 2018.1.28 2018.2.21 2018.5.24
124	172	Factorial Trailing Zeroes	Java	Easy	2017.10.20	Math	2018.9.15
125	7	Reverse Integer	Java	Easy	2017.10.22	Math
126	190	Reverse Bits	Java	Easy	2017.10.25	Bit Manipulation
127	3	Longest Substring Without Repeating Characters	Java	Medium	2017.10.27	HashTable, Two Pointers, String	2018.1.22 2018.9.6 2018.9.21 2018.10.17 2018.10.23 2018.11.15 2019.1.10
128	50	Pow(x, n)	Java	Medium	2017.11.1	Math	2018.3.19 2018.10.1 2018.11.3 2018.11.7 2018.11.12
129	374	Guess Number Higher or Lower	Java	Easy	2017.11.2	Binary Search	2018.3.22 2018.10.12
130	242	Valid Anagram	Java	Easy	2017.11.4	Hash Table, Sort	2018.10.11
131	110	Balanced Binary Tree	Java	Easy	2017.11.5	Tree, DFS	2017.12.31 2018.4.26 2018.10.14 2018.10.24 2018.11.13
132	168	Excel Sheet Column Title	Java	Easy	2017.11.5	Math	2018.1.3
133	11	Container With Most Water	Java	Medium	2017.11.7	Array, Two Pointers	2018.1.3 2018.9.23
134	238	Product of Array Except Self	Java	Medium	2017.11.8	Array	2018.1.4 2018.4.17 2018.10.27 2018.11.9 2018.11.11
135	5	Longest Palindromic Substring	Java	Medium	2017.11.11	String	2018.1.3 2018.3.19 2018.4.17 2018.9.23
136	580	Count Student Number in Departments	SQL	Medium	2017.11.11	Database	2018.1.2
137	243	Shortest Word Distance	Java	Easy	2017.11.12	Array	2018.1.2
138	661	Image Smoother	Java	Easy	2017.11.12	Array	2018.1.3
139	586	Customer Placing the Largest Number of Orders	SQL	Easy	2017.11.12	Database
140	595	Big Countries	SQL	Easy	2017.11.12	Database	2018.2.5
141	339	Nested List Weight Sum	Java	Easy	2017.11.13	DFS	2018.1.8 2018.2.19 2018.10.4 2018.10.19
142	728	Self Dividing Numbers	Java	Easy	2017.11.20	Math
143	346	Moving Average from Data Stream	Java	Easy	2017.11.20	Design, Queue	2018.10.6 2018.10.28
144	266	Palindrome Permutation	Java	Easy	2017.11.20	HashMap	2018.10.10 2018.10.19
145	682	Baseball Game	Java	Easy	2017.11.20	Stack	2018.4.10
146	669	Trim a Binary Search Tree	Java	Easy	2017.11.20	Tree
147	293	Flip Game	Java	Easy	2017.11.21	String
148	637	Average of Levels in Binary Tree	Java	Easy	2017.11.21	Tree
149	696	Count Binary Substrings	Java	Easy	2017.11.22	String
150	717	1-bit and 2-bit Characters	Java	Easy	2017.11.24	Array
151	653	Two Sum IV	Java	Easy	2017.11.24	Tree	2017.12.13 2018.4.19
152	252	Meeting Rooms	Java	Easy	2017.11.25	Sort	2018.10.11 2018.10.26
153	504	Base 7	Java	Easy	2017.11.25	Math	2018.2.3
154	477	Total Hamming Distance	Java	Easy	2017.11.25	Math, Bit manipulation
155	112	Path Sum	Java	Easy	2017.11.25	Tree, DFS	2018.3.15 2018.5.6
156	734	Sentence Similarity	Java	Easy	2017.11.25	Hash Table	2018.9.12
157	733	Flood Fill	Java	Easy	2017.11.25	DFS	2018.10.11
158	735	Asteroid Collision	Java	Medium	2017.11.26	Stack
159	170	Two Sum III	Java	Easy	2017.11.26	Hash Table, Design	2017.12.13 2018.10.16 2019.1.11
160	256	Paint House	Java	Easy	2017.11.27	Dynamic Programming	2017.12.19 2018.1.28 2018.2.21 2018.5.23
161	342	Power of Four	Java	Easy	2017.11.27	Bit Manipulation
162	231	Power of Two	Java	Easy	2017.11.27	Math, Bit Manipulation
163	326	Power of Three	Java	Easy	2017.11.27	Math
164	654	Maximum Binary Tree	Java	Medium	2017.11.27	Stack	2018.11.17
165	191	Number of 1 Bits	Java	Easy	2017.11.27	Bit manipulation	2018.7.14 2018.9.8
166	624	Maximum Distance in Arrays	Java	Easy	2017.11.27	Array
167	197	Rising Temperature	SQL	Easy	2017.11.27	Database
168	96	Unique Binary Search Trees	Java	Easy	2017.11.28	Dynamic Programming, Tree	2017.12.19 2017.12.31 2018.5.9 2018.10.3
169	338	Counting Bits	Java	Medium	2017.11.29	Dynamic Programming, Bit manipulation	2017.12.18 2019.1.27
170	257	Binary Tree Paths	Java	Easy	2017.11.29	Tree, DFS	2018.10.12 2018.10.24 2018.11.11
171	404	Sum of Left Leaves	Java	Easy	2017.11.29	Tree	2018.3.5 2018.4.2
172	739	Daily Temperatures	Java	Medium	2017.12.2	Stack	2017.12.4
173	738	Monotone Incresing Digits	Java	Medium	2017.12.2	Greedy	2017.12.4
174	6	ZigZag Conversion	Java	Medium	2017.12.7	String	2018.9.23
175	15	3Sum	Java	Medium	2017.12.7	Array, Two Pointers	2018.3.26 2018.3.28 2018.3.29 2018.9.23 2018.10.25 2018.11.10
176	16	3Sum Closest	Java	Medium	2017.12.8	Array, Two Pointers	2018.3.29 2018.9.23
177	259	3Sum Smaller	Java	Medium	2017.12.8	Array, Two Pointers	2018.3.29 2018.11.26
178	18	4Sum	Java	Medium	2017.12.8	Array, Two Pointers	2018.9.24
179	454	4Sum II	Java	Medium	2017.12.8	Array, Hash Table
180	287	Find the Duplicate Number	Java	Medium	2017.12.8	Array, Two Pointers, Binary Search	2018.3.31 2018.4.17 2018.11.7
181	80	[Remove Duplicates from Sorted Array II][80]	Java	Medium	2017.12.8	Array, Two Pointers	2018.10.2
182	107	Binary Tree Level Order Traversal II	Java	Easy	2017.12.9	Tree, BFS	2018.2.13 2018.3.15 2018.4.24 2018.5.29
183	278	First Bad Version	Java	Easy	2017.12.9	Binary Search	2018.3.22 2018.10.16
184	744	[Find Smallest Letter Greater Than Target][744]	Java	Easy	2017.12.9
185	17	Letter Combinations of a Phone Number	Java	Medium	2017.12.10	String, Backtracking	2018.4.24 2018.9.24 2018.10.27 2018.11.12 2018.12.5
186	151	Reverse Words in a String	Java	Medium	2017.12.10	String	2018.2.16 2018.10.26
187	186	Reverse Words in a String II	Java	Medium	2017.12.10	String	2018.2.16 2018.4.16
188	22	Generate Parentheses	Java	Medium	2017.12.10	String, Backtracking	2018.9.24 2018.10.28
189	437	Path Sum III	Java	Easy	2017.12.10	Tree	2018.5.6 2018.10.14 2018.11.18
190	458	Poor Pigs	Java	Easy	2017.12.11	Math
191	720	Longest Word in Dictionary	Java	Easy	2017.12.12	HashTable, Trie
192	538	Convert BST to Greater Tree	Java	Easy	2017.12.12	Tree
193	544	Output Contest Matches	Java	Medium	2017.12.12	String
194	419	Battleships in a Board	Java	Medium	2017.12.12	Array	2018.5.23
195	415	Add Strings	Java	Easy	2017.12.13	Math	2018.10.14 2018.11.12
196	208	Implement Trie (Prefix Tree)	Java	Medium	2017.12.14	Design Trie
197	211	Add and Search Word - Data structure design	Java	Medium	2017.12.14	Backtracking, Design, Trie	2018.10.22 2018.11.11
198	369	Plus One Linked List	Java	Medium	2017.12.14	Linked List	2018.2.8 2018.2.11
199	104	Maximum Depth of Binary Tree	Java	Easy	2017.12.15	Tree, DFS	2017.12.30 2018.1.5 2018.2.17 2018.10.15
200	202	Happy Number	Java	Easy	2017.12.15	Hash Table, Math
201	725	Split Linked List in Parts	Java	Medium	2017.12.16	Linked List	2018.12.5
202	215	Kth Largest Element in an Array	Java	Medium	2017.12.16	Divide and Conquer, Heap	2018.4.2 2018.10.18 2018.11.11 2019.1.14
203	748	Shortest Completing Word	Java	Easy	2017.12.16	Hash Table
204	740	Delete and Earn	Java	Medium	2017.12.6	Dynamic Programming	2017.12.17 2018.1.9
205	746	Min Cost Climbing Stairs	Java	Easy	2017.12.17	Dynamic Programming	2018.1.27 2018.2.21 2018.4.12 2018.5.1 2018.5.23ff
206	276	Paint House	Java	Easy	2017.12.17	Dynamic Programming	2018.1.29
207	91	Decode Ways	Java	Medium	2017.12.18	Dynamic Programming	2018.10.3 2018.10.10 2018.10.27 2018.11.11 2018.11.17
208	213	House Robber II	Java	Medium	2017.12.19	Dynamic Programming	2018.11.10
209	337	House Robber III	Java	Medium	2017.12.19	Dynamic Programming	2018.11.10
210	647	Palindromic Substrings	Java	Medium	2017.12.19	Dynamic Programming
211	413	Arithmetic Slices	Java	Medium	2017.12.20	Dynamic Programming
212	712	Minimum ASCII Delete Sum for Two Strings	Java	Medium	2017.12.20	Dynamic Programming
213	357	Count Numbers with Unique Digits	Java	Medium	2017.12.20	Dynamic Programming
214	62	Unique Paths	Java	Medium	2017.12.20	Dynamic Programming	2018.1.30 2018.3.7 2018.10.2 2019.1.16
215	63	Unique Paths II	Java	Medium	2017.12.20	Dynamic Programming	2018.1.30 2018.3.7 2018.6.9 2018.10.2
216	64	Minimum Path Sum	Java	Medium	2017.12.21	Dynamic Programming	2018.10.1 2018.10.13
217	120	Triangle	Java	Medium	2017.12.21	Dynamic Programming
218	139	Word Break	Java	Medium	2017.12.21	Dynamic Programming	2018.5.17 2018.5.26
219	258	Add Digits	Java	Easy	2016.3.21	Math	2017.12.21 2018.6.30
220	401	Binary Watch	Java	Easy	2017.12.21 2017.12.22	Bit manipulation Backtracking
221	52	N-Queens II	Java	Hard	2017.12.22	Backtracking
222	51	N-Queens	Java	Hard	2017.12.22	Backtracking
223	152	Maximum Product Subarray	Java	Medium	2017.12.22	Dynamic Programming	2018.4.29 2019.1.10
224	474	[Ones and Zeroes][474]	Java	Medium	2017.12.23	Dynamic Programming
225	79	Word Search	Java	Medium	2017.12.25	Array, Backtracking	2018.5.25 2018.10.2 2018.11.9
226	674	Longest Continuous Increasing Subsequence	Java	Easy	2017.12.25	Array	2018.10.12 2018.11.3 2018.11.6 2018.11.12
227	175	Combine Two Tables	SQL	Easy	2017.12.27	DataBase
228	176	Second Highest Salary	SQL	Easy	2017.12.27	DataBase
229	177	Nth Highest Salary	SQL	Medium	2017.12.27	DataBase
230	178	Rank Scores	SQL	Medium	2017.12.27	DataBase
231	180	Consecutive Numbers	SQL	Medium	2017.12.27	DataBase
232	181	Employees Earning More Than Their Managers	SQL	Easy	2017.12.27	DataBase
233	182	Duplicate Emails	SQL	Easy	2017.12.27	DataBase
234	183	Customers Who Never Order	SQL	Easy	2017.12.27	DataBase
235	184	Department Highest Salary	SQL	Medium	2017.12.27	DataBase
236	677	Map Sum Pairs	Java	Medium	2017.12.28	Trie
237	676	Implement Magic Dictionary	Java	Medium	2017.12.29	Trie
238	185	Department Top Three Salaries	SQL	Hard	2017.12.29	DataBase
239	196	Delete Duplicate Emails	SQL	Easy	2017.12.29	DataBase
240	627	Swap Salary	SQL	Easy	2017.12.29	DataBase
241	648	Replace Words	Java	Medium	2017.12.29	Trie
242	421	Maximum XOR of Two Numbers in an Array	Java	Medium	2017.12.30	Bit Manipulation
243	620	Not Boring Movies	SQL	Easy	2017.12.30	DataBase
244	619	Biggest Single Number	SQL	Easy	2017.12.30	DataBase
245	226	Invert Binary Tree	Java	Easy	2017.12.30	Tree	2018.1.11 2018.2.5 2018.5.7 2018.5.16 2018.11.18
246	235	Lowest Common Ancestor of a Binary Search Tree	Java	Easy	2017.12.31	Tree	2018.4.12 2018.7.19 2018.9.16 2018.10.24
247	613	Shortest Distance in a Line	SQL	Easy	2017.12.31	DataBase
248	577	Employee Bonus	SQL	Easy	2017.12.31	DataBase
249	584	Find Customer Referee	SQL	Easy	2017.12.31	DataBase
250	124	Binary Tree Maximum Path Sum	Java	Hard	2018.1.1	Tree	2018.2.9 2018.11.11
251	244	Shortest Word Distance II	Java	Medium	2018.1.2	HashTable, Array
252	245	Shortest Word Distance III	Java	Medium	2018.1.2	Array
253	229	Majority Element II	Java	Medium	2018.1.6	Array	2018.3.2
254	570	Managers with at Least 5 Direct Reports	SQL	Medium	2018.1.6	DataBase
255	596	Classes More Than 5 Students	SQL	Easy	2018.1.6	DataBase
256	56	Merge Intervals	Java	Medium	2018.1.6	Array	2018.2.16 2018.4.23 2018.10.1 2018.10.27 2018.11.11
257	610	Triangle Judgement	SQL	Easy	2018.1.9	DataBase
258	607	Sales Person	SQL	Easy	2018.1.11	DataBase
259	556	Next Greater Element III	Java	Medium	2018.1.13	String	2018.11.3	LC31 Next Permutation
260	72	Edit Distance	Java	Hard	2018.1.18	Dynamic Programming	2019.1.15
261	283	Move Zeroes	Java	Easy	2018.1.18	Array, Two Pointers	2018.10.11 2018.11.11
262	766	Toeplitz Matrix	Java	Easy	2018.1.21	Array
263	769	Max Chunks To Make Sorted	Java	Medium	2018.1.21	Array
264	76	Minimum Window Substring	Java	Hard	2018.1.23	HashTable, Two Pointers, String	2018.10.26
265	159	Longest Substring with At Most Two Distinct Characters	Java	Hard	2018.1.23	HashTable, Two Pointers, String	2018.10.18
266	340	Longest Substring with At Most K Distinct Characters	Java	Hard	2018.1.23	HashTable, Two Pointers, String	2018.10.18 2018.10.27 2018.11.15
267	697	Degree of an Array	Java	Easy	2018.1.23	Array
268	608	Tree Node	SQL	Medium	2018.1.25	DataBase	2018.3.30
269	775	Global and Local Inversions	Java	Medium	2018.1.29	Array, Math
270	750	Number of Corner Rectangles	Java	Medium	2018.1.30	Dynamic Programming	2018.2.21
271	42	Trapping Rain Water	Java	Hard	2018.1.30	Array, Dynamic Programming, Two pointers, Stack	2018.10.22
272	217	Contains Duplicate	Java	Easy	2018.2.2	Array, HashMap	2018.2.14
273	537	Complex Number Multiplication	Java	Medium	2018.2.4	String, Math
274	598	Range Addition II	Java	Easy	2018.2.5	Math
275	771	Jewels and Stones	Java	Easy	2018.2.5	Hash Table	2018.2.24 2018.4.9
276	779	K-th Symbol in Grammar	Java	Medium	2018.2.7	Recursion
277	783	Minimum Distance Between BST Nodes	Java	Easy	2018.2.10	Tree
278	781	Rabbits in Forrest	Java	Medium	2018.2.10	HashTable
279	300	[Longest Increasing Subsequence][300]	Java	Medium	2018.2.11	Binary Search, Dynamic Programming	2018.2.23 2018.3.2 2018.11.12 2019.1.27
280	143	Reorder List	Java	Medium	2018.2.12	LinkedList	2018.8.9 2018.10.28 2018.11.11
281	379	Design Phone Directory	Java	Medium	2018.2.12	LinkedList, Design	2018.11.17
282	102	Binary Tree Level Order Traversal	Java	Medium	2018.2.13	Tree, BFS	2018.4.14 2018.4.17 2018.4.24 2018.6.1 2018.9.15 2018.10.3
283	138	Copy List with Random Pointer	Java	Medium	2018.2.13	LinkedList, HashTable	2018.10.6 2018.10.27 2019.1.12
284	161	One Edit Distance	Java	Medium	2018.2.20	String	2018.10.27 2019.1.15
285	384	Shuffle an Array	Java	Medium	2018.2.21	Design
286	364	Nested List Weight Sum II	Java	Medium	2018.2.22	DFS
287	103	Binary Tree Zigzag Level Order Traversal	Java	Medium	2018.2.22	BFS, Tree	2018.4.24 2018.10.3 2018.10.24
288	516	Longest Palindromic Subsequence	Java	Medium	2018.2.23	Dynamic Programming	2018.3.19 2019.2.9
289	322	Coin Change	Java	Medium	2018.2.24	Dynamic Programming	2019.1.16
290	75	Sort Colors	Java	Medium	2018.2.28	Sort	2018.4.4 2018.10.2
291	435	Non-overlapping Intervals	Java	Medium	2018.2.28	Greedy
292	134	Gas Station	Java	Medium	2018.3.1	Greedy
293	518	Coin Change 2	Java	Medium	2018.3.1	Dynamic Programming
294	723	Longest Continuous Increasing Subsequence	Java	Easy	2018.3.1	Array
295	200	Number of Islands	Java	Medium	2018.3.4	DFS, BFS, Union-find	2018.4.4 2018.11.12 2019.1.12
296	543	Diameter of Binary Tree	Java	Easy	2018.3.6	DFS, Tree	2018.10.12 2018.10.24 2018.11.11
297	671	Second Minimum Node In a Binary Tree	Java	Easy	2018.3.6	BFS, Tree	2018.5.25
298	270	Closest Binary Search Tree Value	Java	Easy	2018.3.6	Binary Search, Tree	2018.3.8 2018.6.11 2018.7.9 2018.10.14 2018.10.24 2018.11.13
299	563	Binary Tree Tilt	Java	Easy	2018.3.8	Tree
300	572	Subtree of Another Tree	Java	Easy	2018.3.8	Tree	2018.4.23 2018.10.24
301	501	Find Mode in Binary Search Tree	Java	Easy	2018.3.9	Tree
302	687	Longest Univalue Path	Java	Easy	2018.3.10	Tree
303	513	Find Bottom Left Tree Value	Java	Medium	2018.3.12	Tree	2018.5.30
304	366	Find Leaves of Binary Tree	Java	Medium	2018.3.13	Tree
305	796	Rotate String	Java	Easy	2018.3.14	String
306	515	Find Largest Value in Each Tree Row	Java	Medium	2018.3.14	Tree	2018.5.30
307	250	Count Univalue Subtrees	Java	Medium	2018.3.16	Tree
308	280	Wiggle Sort	Java	Medium	2018.3.20	Array, Sort	2018.5.23
309	116	Populating Next Right Pointers in Each Node	Java	Medium	2018.3.21	Tree
310	33	Search in Rotated Sorted Array	Java	Medium	2018.3.22	Binary Search	2018.3.27 2018.4.24 2018.9.29 2018.10.10 2018.10.26 2018.11.7 2018.11.12
311	162	Find Peak Element	Java	Medium	2018.3.23	Binary Search	2018.8.17 2018.11.6
312	658	Find K Closest Elements	Java	Medium	2018.3.27	Binary Search, Two Pointers	2018.8.2 2018.8.17 2018.10.27
313	127	Word Ladder	Java	Medium	2018.4.6	BFS	2018.4.14 2018.4.23 2018.5.26 2018.6.25 2018.11.13
314	207	Course Schedule	Java	Medium	2018.4.6	Topological Sort	2018.6.6 2018.11.13
315	210	Course Schedule II	Java	Medium	2018.4.7	Topological Sort	2018.4.10 2018.6.6 2018.11.13
316	78	Subsets	Java	Medium	2018.4.7	DFS	2018.4.13 2018.10.1 2018.10.13 2018.10.26
317	31	Next Permutation	Java	Medium	2018.4.8	Array	2018.11.10
318	46	Permutations	Java	Medium	2018.4.8	Backtracking	2018.7.12 2018.10.1 2018.10.27
319	716	Max Stack	Java	Hard	2018.4.11	Stack, Design
320	451	Sort Character By Frequency	Java	Medium	2018.4.11	Heap, HashMap
321	98	Validate Binary Search Tree	Java	Medium	2018.4.11	DFS, Tree	2018.4.21 2018.10.23 2018.11.11 2018.11.13
322	763	Partition Labels	Java	Medium	2018.4.11	Greedy, Two Pointers
323	236	Lowest Common Ancestor of a Binary Tree	Java	Medium	2018.4.12	Tree	2018.9.16 2018.10.24
324	133	Clone Graph	Java	Medium	2018.4.12	Graph, DFS, BFS	2018.10.27
325	535	Encode and Decode TinyURL	Java	Medium	2018.4.13	HashTable, Math
326	817	Linked List Components	Java	Medium	2018.4.14	Linked List	2018.6.21
327	23	Merge k Sorted Lists	Java	Hard	2018.4.15	Linked List, Heap	2018.4.17 2018.7.7 2018.7.11 2018.10.28
328	325	Maximum Size Subarray Sum Equals k	Java	Medium	2018.4.16	HashMap	2018.5.14 2018.10.28 2018.11.12
329	165	Compare Version Numbers	Java	Medium	2018.4.16	String
330	285	Inorder Successor in BST	Java	Medium	2018.4.17	Tree	2018.10.24
331	323	Number of Connected Components in an Undirected Graph	Java	Medium	2018.4.20	Union Find, DFS, BFS, Graph	2018.5.30
332	48	Rotate Image	Java	Medium	2018.4.23	Array	2018.10.1 2018.11.5
333	680	Valid Palindrome II	Java	Easy	2018.4.24	String	2018.10.15 2018.10.26 2018.11.10
334	560	Subarray Sum Equals K	Java	Medium	2018.4.24	Array, Hash Table	2018.10.28 2018.11.10
335	39	Combination Sum	Java	Medium	2018.4.24	Array, Backtracking	2018.10.1 2018.10.25 2019.2.5
336	40	Combination Sum II	Java	Medium	2018.4.24	Array, Backtracking	2018.10.1 2018.10.27 2019.2.5
337	153	Find Minimum in Rotated Sorted Array	Java	Medium	2018.4.26	Array, Binary Search	2018.8.17 2018.11.7
338	114	Flatten Binary Tree to Linked List	Java	Medium	2018.4.27	Tree, DFS	2018.11.13
339	824	Goat Latin	Java	Easy	2018.5.2	String	2018.10.10 2018.10.19
340	444	Sequence Reconstruction	Java	Medium	2018.5.3	Graph, Topological Sort
341	397	Integer Replacement	Java	Medium	2018.5.3	Math, Bit Manipulation
342	137	[Single Number II][137]	Java	Medium	2018.5.4	HashTable, Bit Manipulation、	2018.10.30
343	742	Closest Leaf in a Binary Tree	Java	Medium	2018.5.5	Tree
344	113	Path Sum II	Java	Medium	2018.5.6	Tree, DFS
345	95	Unique Binary Search Tree II	Java	Medium	2018.5.9	Tree, Divide and Conquar
346	199	Binary Tree Right Side View	Java	Medium	2018.5.10	Tree, BFS, DFS	2018.6.1 2018.10.24 2018.11.5 2018.11.11
347	370	Range Addition	Java	Meidum	2018.5.11	Array
348	406	Queue Reconstruction by Height	Java	Medium	2018.5.11	Greedy
349	531	[Lonely Pixel I][531]	Java	Medium	2018.5.11	Array, DFS
350	281	Zigzag Iterator	Java	Medium	2018.5.12	Design	2018.11.17
351	530	Minimum Absolute Difference in BST	Java	Easy	2018.5.13	Binary Search Tree
352	506	Relative Ranks	Java	Easy	2018.5.14	Array
353	298	Binary Tree Longest Consecutive Sequence	Java	Medium	2018.5.14	Tree	2019.2.11
354	378	Kth Smallest Element in a Sorted Matrix	Java	Medium	2018.5.15	Binary Search, Heap	2018.10.18
355	665	Non-decreasing Array	Java	Easy	2018.5.15	Array
356	686	Repeated String Match	Java	Easy	2018.5.17	String	2018.5.18
357	422	Valid Word Square	Java	Easy	2018.5.17	String
358	361	Bomb Enemy	Java	Medium	2018.5.17	Dynamic Programming
359	482	License Key Formating	Java	Easy	2018.5.18	String
360	246	Strobogrammatic Number	Java	Easy	2018.5.19	Hash Table, Math	2018.10.14 2018.11.12
361	838	Push Dominoes	Java	Medium	2018.5.20	String
362	836	Rectangle Overlap	Java	Easy	2018.5.20	Math
363	507	Perfect Number	Java	Easy	2018.5.20	Math
364	784	Letter Case Permutation	Java	Easy	2018.5.21	Backtracking
365	443	String Compression	Java	Easy	2018.5.21	String	2018.10.28
366	408	Valid Word Abbreviation	Java	Easy	2018.5.21	String	2018.10.26 2018.11.17
367	724	Find Pivot Index	Java	Easy	2018.5.21	Array
368	633	Sum Of Square Numbers	Java	Easy	2018.5.22	Math
369	367	Valid Perfect Square	Java	Easy	2018.5.22	Math, Binary Search
370	405	Convert a Number to Hexadecimal	Java	Easy	2018.5.22	Bit Manipulation
371	767	Reorganize String	Java	Medium	2018.5.23	String, Heap, Greedy, Sort
372	441	Arranging Coins	Java	Easy	2018.5.24	Math, Binary Search
373	255	Verify Preorder Sequence in Binary Search Tree	Java	Medium	2018.5.26	Stack, Tree
374	841	Keys and Rooms	Java	Medium	2018.5.27	DFS, Graph
375	813	Largest Sum of Averages	Java	Medium	2018.5.28	Dynamic Programming
376	490	The Maze	Java	Medium	2018.5.31	BFS, DFS
377	752	Open the lock	Java	Medium	2018.6.1	BFS	2018.6.4 2018.6.13
378	505	The Maze II	Java	Medium	2018.6.2	BFS
379	844	Backspace String Compare	Java	Easy	2018.6.3	Two Pointers, Stack
380	845	Longest Mountain in Array	Java	Medium	2018.6.3	Two Pointers	2018.9.20
381	846	Hand of Straights	Java	Medium	2018.6.6	Map	2018.6.14
382	729	My Calendar I	Java	Medium	2018.6.7	TreeMap	2018.6.13 2018.10.27
383	731	My Calendar II	Java	Medium	2018.6.7	TreeMap	2018.6.14
384	271	Encode and Decode Strings	Java	Medium	2018.6.9	String	2018.6.13
385	849	Maximize Distance to Closest Person	Java	Easy	2018.6.10	Array
386	848	Shifting Letters	Java	Medium	2018.6.10	String
387	851	Loud and Rich	Java	Medium	2018.6.10	DFS
388	297	Serialize and Deserialize Binary Tree	Java	Hard	2018.6.12	Tree, Design	2018.6.13 2018.10.24
389	826	Most Profit Assigning Work	Java	Medium	2018.6.12	Two Pointers	2018.6.13 2018.8.10
390	842	[Split Array into Fibonacci Sequence][842]	Java	Medium	2018.6.14	String, Backtracking, Greedy	2018.6.15
391	604	Design Compressed String Iterator	Java	Easy	2018.6.16	Design
392	852	Peak Index in a Mountain Array	Java	Easy	2018.6.17	Binary Search
393	853	Car Fleet	Java	Medium	2018.6.17	Array
394	855	Exam Room	Java	Medium	2018.6.17	Design	2018.6.19
395	801	Minimum Swaps To Make Sequences Increasing	Java	Medium	2018.6.18	Dynamic Programming	2018.6.19
396	126	Word Ladder II	Java	Hard	2018.6.23	BFS
397	859	Buddy Strings	Java	Easy	2018.6.24	String
398	856	Score of Parentheses	Java	Medium	2018.6.24	DFS
399	825	Friends Of Appropriate Ages	Java	Medium	2018.6.25	Array
400	792	Number of Matching Subsequences	Java	Medium	2018.6.26	Array
401	583	Delete Operation for Two Strings	Java	Medium	2018.6.27	String, Dynamic Programming
402	146	LRU Cache	Java	Hard	2018.6.28	Design	2018.7.5 2018.8.8 2018.10.27
403	4	Median of Two Sorted Arrays	Java	Hard	2018.6.29	Array, Binary Search	2018.6.30 2018.10.27 2018.11.15
404	860	Lemonade Change	Java	Easy	2018.7.1	Array
405	861	Score After Flipping Matrix	Java	Medium	2018.7.6	Greedy
406	867	Transpose Matrix	Java	Easy	2018.7.8	Array
407	866	Smallest Subtree with all the Deepest Nodes	Java	Medium	2018.7.8	Tree
408	47	Permutations II	Java	Medium	2018.7.12	Backtracking	2018.10.1 2018.10.27
409	868	Binary Gap	Java	Easy	2018.7.15	Bit Manipulation
410	869	Reordered Power of 2	Java	Medium	2018.7.15	DFS, Bit Manipulation
411	470	Implement Rand10 Using Rand7	Java	Medium	2018.7.16	Random, Math
412	871	Minimum Number of Refueling Stops	Java	Hard	2018.7.16	Dynamic Programming	2018.8.8
413	709	To Lower Case	Java	Easy	2018.7.21	String
414	492	Construct the Rectangle	Java	Easy	2018.7.21	Array
415	872	Leaf-Similar Trees	Java	Easy	2018.7.23	Tree
416	874	Walking Robot Simulation	Java	Easy	2018.7.23	Array
417	873	Length of Longest Fibonacci Subsequence	Java	Medium	2018.7.24	Dynamic Programming, Array
418	875	Koko Eating Bananas	Java	Medium	2018.7.24	Binary Search
419	540	Single Element in a Sorted Array	Java	Medium	2018.7.25	Array
420	700	Search in a Binary Search Tree	Java	Easy	2018.7.26	Tree
421	429	N-ary Tree Level Order Traversal	Java	Easy	2018.7.26	Tree, BFS	2019.2.10
422	528	Random Pick with Weight	Java	Medium	2018.7.30	Binary Search, Random
423	876	Middle of the Linked List	Java	Easy	2018.7.30	Linked List	2018.10.18
424	877	Stone Game	Java	Medium	2018.7.30	Math, Dynamic Programming	2018.11.9
425	478	Generate Random Point in a Circle	Java	Medium	2018.7.31	Math, Random, Rejection Sampling
426	704	Binary Search	Java	Easy	2018.8.1	Binary Search
427	123	Best Time to Buy and Sell Stock III	Java	Hard	2018.8.2	Dynamic Programming, Array	2019.1.28 2019.2.12
428	809	Expressive Words	Java	Medium	2018.8.3	String	2019.2.10
429	887	Projection Area of 3D Shapes	Java	Easy	2018.8.5	Math
430	881	Boats to Save People	Java	Medium	2018.8.5	Greedy, Two Pointers	2018.8.15
431	880	Decoded String at Index	Java	Medium	2018.8.7	String
432	673	Number of Longest Increasing Subsequence	Java	Medium	2018.8.9	Dynamic Programming
433	884	Uncommon Words from Two Sentences	Java	Easy	2018.8.15	Hash Table
434	179	Largest Number	Java	Meidum	2018.8.19	Sort	2018.9.15
435	888	Fair Candy Swap	Java	Easy	2018.8.19	Array
436	889	Construct Binary Tree from Preorder and Postorder Traversal	Java	Medium	2018.8.20	Tree
437	890	Find and Replace Pattern	Java	Medium	2018.8.20	String
438	886	Possible Bipartition	Java	Medium	2018.8.21	DFS
439	885	Spiral Matrix III	Java	Medium	2018.8.22	Math	2018.10.22
440	703	Kth Largest Element in a Stream	Java	Easy	2018.8.22	Heap	2018.10.18
441	559	Maximum Depth of N-ary Tree	Java	Easy	2018.8.23	Tree, DFS, BFS
442	589	N-ary Tree Preorder Traversal	Java	Easy	2018.8.24	Tree
443	590	N-ary Tree Postorder Traversal	Java	Easy	2018.8.24	Tree
444	892	Surface Area of 3D Shapes	Java	Easy	2018.8.27	Math
445	893	Groups of Special-Equivalent Strings	Java	Easy	2018.8.28	String
446	894	All Possible Full Binary Trees	Java	Medium	2018.8.28	Tree
447	253	Meeting Rooms II	Java	Medium	2018.8.29	Heap, Greedy, Sort	2018.10.19 2018.10.26 2018.11.10 2019.1.7 2019.1.14
448	54	Spiral Matrix	Java	Medium	2018.8.29	Array	2018.10.1 2018.10.22
449	59	Spiral Matrix II	Java	Medium	2018.8.29	Array	2018.10.1 2018.10.22
450	681	Next Closest Time	Java	Medium	2018.8.30	String	2019.1.15
451	49	Group Anagrams	Java	Medium	2018.8.31	HashTable	2018.10.1 2018.10.10
452	896	Monotonic Array	Java	Easy	2018.9.1	Array	2018.10.11 2018.10.19
453	897	Incresing Order Search Tree	Java	Easy	2018.9.1	Tree
454	898	Bitwise ORs of Subarrays	Java	Medium	2018.9.1	Dynamic Programming
455	227	Basic Calculator II	Java	Medium	2018.9.3	String	2018.10.27
456	240	Search a 2D Matrix II	Java	Medium	2018.9.4	Binary Search	2018.11.7
457	621	Task Scheduler	Java	Medium	2018.9.5	Array, Greedy, Queue	2018.10.15 2018.11.10 2019.1.7
458	220	Contains Duplicate III	Java	Medium	2018.9.6	Binary Search Tree
459	900	RLE Iterator	Java	Medium	2018.9.13	Array
460	264	Ugly Number II	Java	Medium	2018.9.15	Math, Dynamic Programming, Heap
461	905	Sort Array By Parity	Java	Easy	2018.9.15	Array
462	904	Fruit Into Baskets	Java	Medium	2018.9.15	Two Pointers	2019.1.14
463	907	Sum of Subarray Minimums	Java	Medium	2018.9.15	Stack
464	906	Super Palindromes	Java	Hard	2018.9.17	Math
465	698	Partition to K Equal Sum Subsets	Java	Medium	2018.9.21	Recursion
466	911	Online Election	Java	Medium	2018.9.23	HashTable
467	910	Smallest Range II	Java	Medium	2018.9.22	Array
468	909	Snakes and Ladders	Java	Medium	2018.9.22	BFS
469	908	Smallest Range I	Java	Medium	2018.9.22	Array
470	34	Find First and Last Position of Element in Sorted Array	Java	Medium	2018.9.22	Binary Search	2018.10.26 2018.11.12
471	81	Search in Rotated Sorted Array II	Java	Medium	2018.10.2	Binary Search	2018.10.10 2018.10.26 2018.11.7
472	157	Read N Characters Given Read4	Java	Easy	2018.10.4	String	2018.10.28 2018.11.12
473	260	Single Number III	Java	Medium	2018.10.4	Bit Manipulation	2018.10.30
474	277	Find the Celebrity	Java	Medium	2018.10.4	Array	2018.10.27 2018.11.11
475	392	Is Subsequence	Java	Medium	2018.10.5	Binary Search, Two Pointers
476	721	Accounts Merge	Java	Medium	2018.10.6	Union Find, DFS	2018.10.25 2018.11.11
477	74	Search a 2D Matrix	Java	Medium	2018.10.6	Array	2018.11.7
478	917	Reverse Only Letters	Java	Easy	2018.10.6	Two Pointer
479	918	Maxiumum Sum Circular Subarray	Java	Medium	2018.10.6	Array
480	919	Complete Binary Tree Inserter	Java	Medium	2018.10.6	Tree
481	494	Target Sum	Java	Medium	2018.10.7	Dynamic Programming, DFS	2018.10.15
482	523	Continuous Subarray Sum	Java	Medium	2018.10.7	Dynamic Programming, HashMap	2018.11.11
483	360	Sort Transformed Array	Java	Medium	2018.10.7	Two Pointers
484	129	Sum Root to Leaf Numbers	Java	Medium	2018.10.7	DFS	2018.11.18
485	498	Diagonal Traverse	Java	Medium	2018.10.8	Array	2018.10.22
486	314	Binary Tree Vertical Order Traversal	Java	Medium	2018.10.8	Tree, Hash Table	2018.10.15 2018.10.23 2018.11.11
487	785	Is Graph Bipartite	Java	Medium	2018.10.9	Graph, DFS, BFS	2018.10.27 2018.11.11
488	678	Valid Patrenthesis String	Java	Medium	2018.10.9	Greedy
489	73	Set Matrix Zeroes	Java	Medium	2018.10.9	Array
490	398	Random Pick Index	Java	Medium	2018.10.10	Reservoir Sampling	2018.11.12
491	209	Minimum Size Subarray Sum	Java	Medium	2018.10.10	Array, Two Pointers, Binary Search	2018.10.17 2018.10.23 2018.10.28 2018.11.15
492	688	Knight Probability in Chessboard	Java	Medium	2018.10.10	Dynamic Programming
493	524	Longest Word in Dictionary through Deleting	Java	Medium	2018.10.10	Two Pointers, Sort
494	304	Range Sum Query 2D - Immutble	Java	Medium	2018.10.10	Dynamic Programming
495	449	Serialize and Deserialize BST	Java	Medium	2018.10.11	Tree
496	426	Convert Binary Search Tree to Sorted Doubly Linked List	Java	Medium	2018.10.11	Tree	2018.10.23 2018.11.10
497	251	Flatten 2D Vector	Java	Medium	2018.10.11	Design	2018.11.12
498	395	Longest Substring with At Least K Repeating Characters	Java	Medium	2018.10.11	Recursion
499	416	Partition Equal Subset Sum	Java	Medium	2018.10.12	Dynamic Programming
500	90	Subsets II	Java	Medium	2018.10.13	Backtracking	2018.10.26
501	430	Flatten a Multilevel Doubly Linked List	Java	Medium	2018.10.14	LinkedList, DFS	2018.10.27
502	722	Remove Comments	Java	Medium	2018.10.14	String
503	662	Maximum Width of Binary Tree	Java	Medium	2018.10.15	Tree
504	230	Kth Smallest Element in a BST	Java	Medium	2018.10.18	Tree, Binary Search
505	925	Long Pressed Name	Java	Easy	2018.10.21	String
506	926	Flip String to Monotone Increasing	Java	Medium	2018.10.21	String
507	273	Integer to English Words	Java	Hard	2018.10.21	String	2018.11.17
508	301	Remove Invalid Parentheses	Java	Hard	2018.10.22	Backtracking
509	65	Valid Number	Java	Hard	2018.10.22	Math, String	2018.10.25
510	311	Sparse Matrix Multiplication	Java	Medium	2018.10.22	Hash Table
511	282	Expression Add Operators	Java	Hard	2018.10.22	DFS, BackTracking
512	99	Recover Binary Search Tree	Java	Hard	2018.10.24	DFS, Tree
513	428	Serialize and Deserialize N-ary Tree	Java	Hard	2018.10.24	Tree
514	305	Number of Islands II	Java	Hard	2018.10.26	Union Find
515	272	Closest Binary Search Tree Value II	Java	Hard	2018.10.26	Stack, Tree
516	128	Longest Consecutive Sequence	Java	Hard	2018.10.26	Union Find, Array
517	403	Frog Jump	Java	Hard	2018.10.26	Dynamic Programming
518	84	Largest Rectangle in Histogram	Java	Hard	2018.10.26	Stack
519	216	Combination Sum III	Java	Medium	2018.10.27	Backtracking	2019.2.5
520	377	Combination Sum IV	Java	Medium	2018.10.27	Dynamic Programming
521	269	Alien Dictionary	Java	Hard	2018.10.27	Topological Sort	2018.11.13
522	791	Custom Sort String	Java	Medium	2018.10.27 2018.11.12	Sort
523	239	Sliding Window Maximum	Java	Hard	2018.10.27	Queue
524	29	[Divide Two Integers][29]	Java	Medium	2018.10.27	Bit Manipulation	2018.11.8 2018.11.11
525	224	Basic Calculator	Java	Hard	2018.10.27	Stack, Math
526	295	Find Median from Data Stream	Java	Hard	2018.10.28	Heap
527	380	Insert Delete GetRandom O(1)	Java	Medium	2018.10.28	Hash Map, Design
528	381	[Insert Delete GetRandom O(1) - - Duplicates Allowed][381]	Java	Hard	2018.10.28	Hash Map, LinkedHashSet, Design	2018.11.5
529	71	Simplify Path	Java	Medium	2018.10.28	String, Stack
530	286	Walls and Gates	Java	Medium	2018.10.28	BFS	2018.11.17
531	348	[Design Tic-Tac-Toe][348]	Java	Medium	2018.10.28	Design
532	708	Insert into a Cyclic Sorted List	Java	Medium	2018.10.28	LinkedList
533	261	Graph Valid Tree	Java	Medium	2018.10.30	Union Find
534	221	Maximal Square	Java	Medium	2018.11.3	Stack, Dynamic Programming	2018.11.8
535	154	Find Minimum in Rotated Sorted Array II	Java	Hard	2018.11.7	Binary Search
536	644	Maximum Average Subarray II	Java	Hard	2018.11.8	Binary Search
537	486	Predict the Winner	Java	Medium	2018.11.9	Dynamic Programming, Minimax
538	10	Regular Expression Matching	Java	Hard	2018.11.11	Dynamic Programming, Backtracking	2018.11.16
539	43	Multiply Strings	Java	Medium	2018,11,11	String, Math
540	382	Linked List Random Node	Java	Medium	2018.11.12	Reservoir Sampling
541	678	Valid Parenthesis String	Java	Medium	2018.11.12	Stack
542	247	Strobogrammatic Number II	Java	Medium	2018.11.12	Recursion	2018.11.17
543	222	Count Complete Tree Nodes	Java	Medium	2018.11.14	Tree
544	307	Range Sum Query - Mutable	Java	Medium	2018.11.15	Binary Indexed Tree
545	689	Maximum Sum of 3 Non-Overlapping Subarrays	Java	Hard	2018.11.16	Array, Dynamic Programming
546	8	String to Integer (atoi)	Java	Medium	2018.11.16	Math, String
547	317	Shortest Distance from All Buildings	Java	Hard	2018.11.16	BFS
548	336	Palindrome Pairs	Java	Hard	2018.11.16	Trie
549	55	Jump Game	Java	Medium	2018.11.16	Dynamic Programming, Greedy	2019.1.16
550	57	Insert Interval	Java	Hard	2018.11.16	Array
551	32	Longest Valid Parentheses	Java	Hard	2018.11.16	Dynamic Programming
552	567	Permutation in String	Java	Medium	2018.11.16	Sliding Window
553	117	Populating Next Right Pointers in Each Node II	Java	Medium	2018.11.16	Tree
554	636	Exclusive Time of Functions	Java	Medium	2018.11.16	Stack
555	44	Wildcard Matching	Java	Hard	2018.11.16	Dynamic Programming
556	452	Minimum Number of Arrows to Burst Balloons	Java	Medium	2018.11.17	Greedy
557	329	Longest Increasing Path in a Matrix	Java	Hard	2018.11.17	DFS, Memorization
558	291	Word Pattern II	Java	Hard	2018.11.17	Backtracking
559	140	Word Break II	Java	Hard	2018.11.17	Dynamic Programming, Backtracking
560	158	Read N Characters Given Read4 II	Java	Hard	2018.11.17	String
561	862	Shortest Subarray with Sum at Least K	Java	Hard	2018.11.17	Deque
562	493	Reverse Pairs	Java	Hard	2018.11.17	Divide and Conquer
563	99
564	554	Brick Wall	Java	Medium	2018.11.17	HashMap
565	248	Strobogrammatic Number III	Java	Hard	2018.11.17	Recuision
566	622	Design Circular Queue	Java	Medium	2018.11.17	Design
567	332	Reconstruct Itinerary	Java	Medium	2018.11.17	HashMap, DFS
568	921	Minimum Add to Make Parentheses Valid	Java	Medium	2018.11.26	Stack, Greedy
569	933	Number of Recent Calls	Java	Easy	2018.11.26	Queue
570	929	Unique Email Addresses	Java	Easy	2018.11.26	String	2019.1.14
571	930	Binary Subarrays With Sum	Java	Medium	2018.11.26	Hash Table, Two Pointers
572	815	Bus Routes	Java	Hard	2018.11.30	BFS
573	390	Elimination Game	Java	Medium	2018.12.1	Math
574	949	Largest Time for Given Digits	Java	Easy	2018.12.1	Math, DFS
575	950	Reveal Cards in Increasing Order	Java	Medium	2018.12.1	Array, Deque
576	951	Flip Equivalent Binary Trees	Java	Medium	2018.12.1	Tree
577	953	Verifying an Alien Dictionary	Java	Easy	2018.12.16	Hash Table
578	954	Array of Doubled Pairs	Java	Medium	2018.12.17	Hash Table
579	955	Delete Columns to Make Sorted II	Java	Medium	2018.12.18	Greedy
580	957	Prison Cells After N Days	Java	Medium	2018.12.19	Hash Table
581	959	Regions Cut By Slashes	Java	Medium	2018.12.21	Union Find
582	958	Check Completeness of a Binary Tree	Java	Medium	2018.12.22	Tree
583	965	Univalued Binary Tree	Java	Easy	2019.1.5	Tree
584	966	Vowel Spellchecker	Java	Medium	2019.1.6	Hash Table, String
585	970	Powerful Integers	Java	Easy	2019.1.7	Math
586	967	Numbers with same consecutive differences	Java	Medium	2019.1.8	Dynamic Programming
587	968	Pancake Sorting	Java	Medium	2019.1.8	Array, Sort
588	971	Flip Binary Tree to Match Preorder Traversal	Java	Medium	2019.1.8	DFS
589	402	Remove K Digits	Java	Medium	2019.1.9	Stack, Greedy	2019.2.10
590	223	Rectangle Area	Java	Medium	2019.1.9	Math
591	309	Best Time To Buy and Sell Stock with Cooldown	Java	Medium	2019.1.9	Dynamic Programming
592	713	Subarray Product Less Than K	Java	Medium	2019.1.10	Two Pointers
593	931	Minimum Falling Path Sum	Java	Medium	2019.1.11	Dynamic Programming
594	932	Beautiful Array	Java	Medium	2019.1.11	Divide and Conquer
595	819	Most Common Word	Java	Easy	2019.1.12	String
596	683	K Empty Slots	Java	Hard	2019.1.16	HashTable
597	743	Network Delay Time	Java	Easy	2019.1.17	Graph
598	787	Cheapest Flight Within K Stops	Java	Medium	2019.1.18	Graph
599	131	Palindrome Partitioning	Java	Medium	2019.1.18	Backtracking
600	279	Perfect Square	Java	Medium	2019.1.18	Dynamic Programming
601	384	Shuffle an Array	Java	Medium	2019.1.18	Design
602	977	Squares of a Sorted Array	Java	Easy	2019.1.20	Two Pointers, Sort
603	978	Longest Turbulent Subarray	Java	Medium	2019.1.26	Two Pointers
604	265	Paint House II	Java	Hard	2019.1.27	Dynamic Programming
605	188	Best Time to Buy and Sell Stock IV	Java	Hard	2019.1.28	Dynamic Programming
606	982	Triples with Bitwise AND Equal To Zero	Java	Hard	2019.1.28	Dynamic Programming
607	979	Distribute Coins in Binary Tree	Java	Medium	2019.1.28	DFS
608	984	String Without AAA or BBB	Java	Easy	2019.2.2	Greedy
609	985	Sum of Even Numbers After Queries	Java	Easy	2019.2.3	Array
610	835	Image Overlap	Java	Medium	2019.2.5	Array
611	132	Palindrome Partitioning II	Java	Hard	2019.2.5	Dynamic Programming
612	399	Evaluate Division	Java	Medium	2019.2.6	Union Find, BFS
613	299	Bulls and Cows	Java	Medium	2019.2.6	Hash Table	2019.2.12
614	87	Scramble String	Java	Hard	2019.2.9	Dynamic Programming
615	312	Burst Balloons	Java	Hard	2019.2.9	Dynamic Programming
616	980	Unique Paths III	Java	Hard	2019.2.10	Backtracking
617	228	Summary Ranges	Java	Medium	2019.2.10	Two Pointers
618	701	Insert Into a Binary Search Tree	Java	Medium	2019.2.11	Tree
619	723	Candy Crush	Java	Medium	2019.2.11	Two Pointers
620	702	Search in a Sorted Array of Unknown Size	Java	Medium	2019.2.11	Binary Search
621	776	Split BST	Java	Medium	2019.2.11	BST
622	684	Redundant Connection	Java	Medium	2019.2.11	Union Find
623	320	Generalized Abbreviation	Java	Medium	2019.2.11	Backtracking
624	249	Group Shifted Strings	Java	Medium	2019.2.11	HashTable
625	386	Lexicographical Numbers	Java	Medium	2019.2.11	DFS
626	549	Binary Tree Longest Consecutive Sequence II	Java	Medium	2019.2.11	Tree
627	424	Longest Repeating Character Replacement	Java	Medium	2019.2.11	Two Pointers, Sliding Window
628	135	Candy	Java	Hard	2019.2.12	Greedy
629	591	Tag Validator	Java	Hard	2019.2.12	Stack
630	562	Longest Line of Consecutive One in Matrix	Java	Medium	2019.2.13	Dynamic Programming
631	737	Sentence Similarity II	Java	Medium	2019.2.13	Union Find
632	640	Solve the Equation	Java	Medium	2019.2.13	Math, Stack
633	659	Split Array into Consecutive Subsequences	Java	Medium	2019.2.13	Heap, Greedy
634	334	Increasing Triplet Subsequence	Java	Medium	2019.2.13	Array
635	450	Delete Node in a BST	Java	Medium	2019.2.13	Tree
636	284	Peeking Iterator	Java	Medium	2019.2.13	Design
637	616	Add Bold Tag in String	Java	Medium	2019.2.13	String
638	388	Longest Absolute File Path	Java	Medium	2019.2.14	String
639	935	Knight Dialer	Java	Medium	2019.2.14	Dynamic Programming
640	433	Minimum Genetic Mutation	Java	Medium	2019.2.14	BFS
641	375	Guess Number Higher or Lower II	Java	Medium	2019.2.14	Dynamic Programming
642	417	Pacific Atlantic Water Flow	Java	Medium	2019.2.14	BFS, DFS
643	115	Distinct Subsequences	Java	Medium	2019.2.14	Dynamic Programming

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