152-Maximum Product Subarray, 169-Majority Element, 189-Rotate Array, 198-House Robber
153-Find Minimum in Rotated Sorted Array(II), 162-Find Peak Element
155-Min Stack, 173-Binary Search Tree Iterator, HARD: 146-LRU Cache, 621-Task Scheduler, 17-Letter Combinations of a Phone Number, HARD: 297-Serialize and Deserialize Binary Tree, 341-Flatten Nested List Iterator, HARD: 428-Serialize and Deserialize N-ary Tree
Fast and slow pointer: 160-Intersection of Two Linked List, 141-Linked List Cycle, 142-Linked List Cycle II, 143-Reorder List
HARD: 164-Maximum Gap(bucket sort and pigeon hole), 147-Insertion Sort List, 148-Sort List(Mergesort), 215-Kth Largest Element in an Array(Heap Sort), HARD: 218-The Skyline Problem(Mergesort)
HARD: 174-Dungeon Game, HARD: 188-Best Time to Buy and Sell Stock IV, HARD: 689-Maximum Sum of 3 Non-Overlapping Subarrays, 91-Decode Ways, HARD: 10-Regular Expression Matching, 139-Word Break, 494-Target Sum, 523-Continuous Subarray Sum, HARD: 568-Maximum Vacation Days, 375-Guess Number Higher or Lower II(MinMax)
187-Repeated DNA Sequence, 191-Number of 1 bits
199-Binary Tree Right Side View(DFS), 200-Number of Islands(DFS), HARD: 301-Remove Invalid Parentheses(BFS), 774-Minimize Max Distance to Gas Station(Binary Search 二分法)
144-Binary Tree Preorder Traversal, HARD: 145-Binary Tree Postorder Traversal, 98-Validate Binary Search Tree, 307-Range Sum Query - Mutable(Binary Index Tree)
150-Evaluate Reverse Polish Notation
HARD: 301-Remove Invalid Parentheses，257-Binary Tree Paths， 543-Diameter of Binary Tree, HARD: 282-Expression Add Operators, 79-Word Search, 38-Count and Say, 486-Predict the Winner
HARD: 76-Minimum Window Substring
HARD: 23-Merge k Sorted Lists
HARD: 685-Redundant Connection II(Union Find)
Combination Sum, Permutations, Restore IP Addresses, Palindrome Partitioning
Subsets, Subsets II, Decode ways, Unique Binary Search Tree, Triangle, Word Break
Binary Tree Inorder Traversal, Unique Binary Search Tree II, Validate Binary Search Tree, Construct Binary Tree from Preorder and Inorder Traversal, Convert Sorted List to Binary Search Tree, Populating Next Right Pointers in Each Node II
Reorder List