307 
Range Sum Query  Mmutable 
Medium 
Segment Tree 
304 
Range Sum Query 2D  Immutable 
Medium 
DP 
303 
Range Sum Query  Immutable 
Easy 
DP 
301 
Remove Invalid Parentheses 
Hard 

300 
Longest Increasing Subsequence 
Medium 
DP 
299 
Bulls and Cows 
Easy 
Hash Map 
297 
Serialize and Deserialize Binary Tree 
Hard 
Tree Travsersal 
295 
Find Median from Data Stream 
Hard 
Heap 
292 
Nim Game 
Easy 

290 
Word Pattern 
Easy 
Hash 
289 
Game of Life 
Meduim 
Array 
287 
Find the Duplicate Number 
Hard 
Two Pointers, Linked list 
284 
Peeking Iterator 
Medium 
Design 
283 
Moving Zeros 
Easy 
two pointers 
282 
Expression Add Operators 
Hard 
DFS, String 
279 
Perfect Squares 
Medium 
BFS, DP 
278 
First Bad Version 
Easy 
binary search 
275 
HIndex II 
Medium 
binary search 
274 
HIndex 
Medium 

273 
Integer to English Words 
Hard 
String 
268 
Missing Number 
Medium 

264 
Ugly Number II 
Medium 

263 
Ugly Number 
Easy 

260 
Single Number III 
Medium 

258 
Add Digits 
Easy 

257 
Binary Tree Paths 
Easy 

242 
Valid Anagram 
Easy 

241 
Different Ways to Add Parentheses 
Medium 

240 
Search a 2D Matrix II 
Medium 

239 
Sliding Window Maximum 
Hard 

238 
Product of Array Except Self 
Medium 

237 
Delete Node in a Linked List 
Easy 

236 
Lowest Common Ancestor of a Binary Tree 
Medium 

235 
Lowest Common Ancestor of a Binary Search Tree 
Easy 

234 
Palindrome Linked List 
Easy 

233 
Number of Digit One 
Hard 

232 
Implement Queue using Stacks 
Easy 

231 
Power of Two 
Easy 

230 
Kth Smallest Element in a BST 
Medium 

229 
Majority Element II 
Medium 

228 
Summary Ranges 
Medium 

227 
Basic Calculator II 
Medium 

226 
Invert Binary Tree 
Easy 

225 
Implement Stack using Queues 
Easy 

224 
Basic Calculator 
Hard 

223 
Rectangle Area 
Easy 

222 
Count Complete Tree Nodes 
Medium 

221 
Maximal Square 
Medium 

220 
Contains Duplicate III 
Medium 

219 
Contains Duplicate II 
Easy 

218 
The Skyline Problem 
Hard 

217 
Contains Duplicate 
Easy 

216 
Combination Sum III 
Medium 

215 
Kth Largest Element in an Array 
Medium 

214 
Shortest Palindrome 
Hard 

213 
House Robber II 
Medium 
DP 
212 
Word Search II 
Hard 

211 
Add and Search Word  Data structure design 
Medium 

210 
Course Schedule II 
Medium 

209 
Minimum Size Subarray Sum 
Medium 

208 
Implement Trie (Prefix Tree) 
Medium 

207 
Course Schedule 
Medium 

206 
Reverse Linked List 
Easy 

205 
Isomorphic Strings 
Easy 

204 
Count Primes 
Easy 

203 
Remove Linked List Elements 
Easy 

202 
Happy Number 
Easy 

201 
Bitwise AND of Numbers Range 
Medium 

200 
Number of Islands 
Medium 

199 
Binary Tree Right Side View 
Medium 

198 
House Robber 
Easy 

191 
Number of 1 Bits 
Easy 

190 
Reverse Bits 
Easy 

189 
Rotate Array 
Easy 

188 
Best Time to Buy and Sell Stock IV 
Hard 

187 
Repeated DNA Sequences 
Medium 

179 
Largest Number 
Medium 

174 
Dungeon Game 
Hard 

173 
Binary Search Tree Iterator 
Medium 

172 
Factorial Trailing Zeroes 
Easy 

171 
Excel Sheet Column Number 
Easy 

169 
Majority Element 
Easy 

168 
Excel Sheet Column Title 
Easy 

167 
Two Sum II  Input array is sorted 
Medium 

166 
Fraction to Recurring Decimal 
Medium 

165 
Compare Version Numbers 
Easy 

164 
Maximum Gap 
Hard 

162 
Find Peak Element 
Medium 

160 
Intersection of Two Linked Lists 
Easy 

155 
Min Stack 
Easy 

154 
Find Minimum in Rotated Sorted Array II 
Hard 

153 
Find Minimum in Rotated Sorted Array 
Medium 

152 
Maximum Product Subarray 
Medium 

151 
Reverse Words in a String 
Medium 

150 
Evaluate Reverse Polish Notation 
Medium 

149 
Max Points on a Line 
Hard 

148 
Sort List 
Medium 

147 
Insertion Sort List 
Medium 

146 
LRU Cache 
Hard 

145 
Binary Tree Postorder Traversal 
Hard 

144 
Binary Tree Preorder Traversal 
Medium 

143 
Reorder List 
Medium 

142 
Linked List Cycle II 
Medium 

141 
Linked List Cycle 
Easy 

140 
Word Break II 
Hard 

139 
Word Break 
Medium 

138 
Copy List with Random Pointer 
Hard 

137 
Single Number II 
Medium 

136 
Single Number 
Easy 

135 
Candy 
Hard 

134 
Gas Station 
Medium 

133 
Clone Graph 
Medium 

132 
Palindrome Partitioning II 
Hard 

131 
Palindrome Partitioning 
Medium 

130 
Surrounded Regions 
Medium 

129 
Sum Root to Leaf Numbers 
Medium 

128 
Longest Consecutive Sequence 
Hard 

127 
Word Ladder 
Medium 

126 
Word Ladder II 
Hard 

125 
Valid Palindrome 
Easy 

124 
Binary Tree Maximum Path Sum 
Hard 

123 
Best Time to Buy and Sell Stock III 
Hard 

122 
Best Time to Buy and Sell Stock II 
Medium 

121 
Best Time to Buy and Sell Stock 
Easy 

120 
Triangle 
Medium 

119 
Pascal's Triangle II 
Easy 

118 
Pascal's Triangle 
Easy 

117 
Populating Next Right Pointers in Each Node II 
Hard 

116 
Populating Next Right Pointers in Each Node 
Medium 

115 
Distinct Subsequences 
Hard 

114 
Flatten Binary Tree to Linked List 
Medium 

113 
Path Sum II 
Medium 

112 
Path Sum 
Easy 

111 
Minimum Depth of Binary Tree 
Easy 

110 
Balanced Binary Tree 
Easy 

109 
Convert Sorted List to Binary Search Tree 
Medium 

108 
Convert Sorted Array to Binary Search Tree 
Medium 

107 
Binary Tree Level Order Traversal II 
Easy 

106 
Construct Binary Tree from Inorder and Postorder Traversal 
Medium 

105 
Construct Binary Tree from Preorder and Inorder Traversal 
Medium 

104 
Maximum Depth of Binary Tree 
Easy 

103 
Binary Tree Zigzag Level Order Traversal 
Medium 

102 
Binary Tree Level Order Traversal 
Easy 

101 
Symmetric Tree 
Easy 

100 
Same Tree 
Easy 

99 
Recover Binary Search Tree 
Hard 

98 
Validate Binary Search Tree 
Medium 

97 
Interleaving String 
Hard 

96 
Unique Binary Search Trees 
Medium 

95 
Unique Binary Search Trees II 
Medium 

94 
Binary Tree Inorder Traversal 
Medium 

93 
Restore IP Addresses 
Medium 

92 
Reverse Linked List II 
Medium 

91 
Decode Ways 
Medium 

90 
Subsets II 
Medium 

89 
Gray Code 
Medium 

88 
Merge Sorted Array 
Easy 

87 
Scramble String 
Hard 

86 
Partition List 
Medium 

85 
Maximal Rectangle 
Hard 

84 
Largest Rectangle in Histogram 
Hard 

83 
Remove Duplicates from Sorted List 
Easy 

82 
Remove Duplicates from Sorted List II 
Medium 

81 
Search in Rotated Sorted Array II 
Medium 

80 
Remove Duplicates from Sorted Array II 
Medium 

79 
Word Search 
Medium 

78 
Subsets 
Medium 

77 
Combinations 
Medium 

76 
Minimum Window Substring 
Hard 

75 
Sort Colors 
Medium 

74 
Search a 2D Matrix 
Medium 

73 
Set Matrix Zeroes 
Medium 

72 
Edit Distance 
Hard 

71 
Simplify Path 
Medium 

70 
Climbing Stairs 
Easy 

69 
Sqrt(x) 
Medium 

68 
Text Justification 
Hard 

67 
Add Binary 
Easy 

66 
Plus One 
Easy 

65 
Valid Number 
Hard 

64 
Minimum Path Sum 
Medium 

63 
Unique Paths II 
Medium 

62 
Unique Paths 
Medium 

61 
Rotate List 
Medium 

60 
Permutation Sequence 
Medium 

59 
Spiral Matrix II 
Medium 

58 
Length of Last Word 
Easy 

57 
Insert Interval 
Hard 

56 
Merge Intervals 
Hard 

55 
Jump Game 
Medium 

54 
Spiral Matrix 
Medium 

53 
Maximum Subarray 
Medium 

52 
NQueens II 
Hard 

51 
NQueens 
Hard 

50 
Pow(x, n) 
Medium 

49 
Group Anagrams 
Medium 

48 
Rotate Image 
Medium 

47 
Permutations II 
Medium 

46 
Permutations 
Medium 

45 
Jump Game II 
Hard 

44 
Wildcard Matching 
Hard 

43 
Multiply Strings 
Medium 

42 
Trapping Rain Water 
Hard 

41 
First Missing Positive 
Hard 

40 
Combination Sum II 
Medium 

39 
Combination Sum 
Medium 

38 
Count and Say 
Easy 

37 
Sudoku Solver 
Hard 

36 
Valid Sudoku 
Easy 

35 
Search Insert Position 
Medium 

34 
Search for a Range 
Medium 

33 
Search in Rotated Sorted Array 
Hard 

32 
Longest Valid Parentheses 
Hard 

31 
Next Permutation 
Medium 

30 
Substring with Concatenation of All Words 
Hard 

29 
Divide Two Integers 
Medium 

28 
Implement strStr() 
Easy 

27 
Remove Element 
Easy 

26 
Remove Duplicates from Sorted Array 
Easy 

25 
Reverse Nodes in kGroup 
Hard 

24 
Swap Nodes in Pairs 
Easy 

23 
Merge k Sorted Lists 
Hard 

22 
Generate Parentheses 
Medium 

21 
Merge Two Sorted Lists 
Easy 

20 
Valid Parentheses 
Easy 

19 
Remove Nth Node From End of List 
Easy 

18 
4Sum 
Medium 

17 
Letter Combinations of a Phone Number 
Medium 

16 
3Sum Closest 
Medium 

15 
3Sum 
Medium 

14 
Longest Common Prefix 
Easy 

13 
Roman to Integer 
Easy 

12 
Integer to Roman 
Medium 

11 
Container With Most Water 
Medium 

10 
Regular Expression Matching 
Hard 

9 
Palindrome Number 
Easy 

8 
String to Integer (atoi) 
Easy 

7 
Reverse Integer 
Easy 

6 
ZigZag Conversion 
Easy 

5 
Longest Palindromic Substring 
Medium 

4 
Median of Two Sorted Arrays 
Hard 

3 
Longest Substring Without Repeating Characters 
Medium 

2 
Add Two Numbers 
Medium 

1 
Two Sum 
Easy 
Hash Map 
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ReplyDelete( Just happened to notice the date : Sunday, April 23, 2017 )
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