1. Majority Element
2. Paint House
3. Pascal's Triangle
4. Two Sum
5. License Key Formatting
6. Max Stack
7. K-diff Pairs in an Array
8. Design HashMap
9. Binary Gap
10. Happy Number
11. Customer Placing the Largest Number of Orders
12. Lowest Common Ancestor of a Binary Search Tree
13. Reverse Linked List
14. Next Greater Element I
15. Valid Parentheses
16. Symmetric Tree
17. Moving Average from Data Stream
18. Range Sum Query - Mutable
19. The Maze
20. Single Element in a Sorted Array
21. LRU Cache
22. Kth Smallest Element in a Sorted Matrix
23. Multiply Strings
24. Integer to Roman
25. Flatten 2D Vector
26. Palindromic Substrings
27. Random Pick with Weight
28. Count Student Number in Departments
29. Time Based Key-Value Store
30. Tree Node
31. Design Log Storage System
32. Insert Delete GetRandom O(1)
33. Encode and Decode Strings
34. Rectangles Area
35. Word Break
36. Masking Personal Information
37. Course Schedule II
38. Flatten Nested List Iterator
39. Construct Binary Tree from Inorder and Postorder Traversal
40. Implement Trie (Prefix Tree)
41. Construct Binary Tree from Preorder and Inorder Traversal
42. Minimum Genetic Mutation
43. Merge Intervals
44. Robot Bounded In Circle
45. Valid Sudoku
46. Minimum Number of Steps to Make Two Strings Anagram
47. Decode Ways
48. Number of Islands
49. Number of Connected Components in an Undirected Graph
50. Investments in 2016
51. Reorganize String
52. Validate IP Address
53. Clone Graph
54. Friend Circles
55. One Edit Distance
56. Design Twitter
57. Tweet Counts Per Frequency
58. Minimum Increment to Make Array Unique
59. Binary Tree Pruning
60. Number of Music Playlists
61. Word Break II
62. Insert Interval
63. Regular Expression Matching
64. Binary Tree Maximum Path Sum
65. The Skyline Problem
66. Trapping Rain Water
67. Largest Rectangle in Histogram
68. Max Points on a Line
69. Design Skiplist
70. Wildcard Matching
71. 24 Game
72. Alien Dictionary
73. Minimum Number of Taps to Open to Water a Garden
74. Trapping Rain Water II
75. Best Meeting Point
76. Minimum Window Substring
77. Find Median from Data Stream
78. Permutation Sequence
79. Text Justification
80. Merge k Sorted Lists
81. Reaching Points
82. Sliding Window Maximum