[第三期活动] 在职刷题打卡，目标工作日一天2题，周末一天5题

Stage II : 分类各个击破
day13-09/19-10 in total，每天没有连续的可用的长时间刷题，对于hard题目实在有限，只能靠周末了，接下来得开始好好刷面经了
binary tree
1. 95. Unique Binary Search Trees II
2. 124. Binary Tree Maximum Path Sum
BFS：
1. 199. Binary Tree Right Side View
2. 116. Populating Next Right Pointers in Each Node
3. 117. Populating Next Right Pointers in Each Node II
4. 127. Word Ladder
5. 126. Word Ladder II
DFS：
1. 112. Path Sum
2. 113. Path Sum II
3. 129. Sum Root to Leaf Numbers

Day_18 (9/18)

Longest palindromic subsequence
Perfect squares

day_17, (9/17)

Edit distance - replace edition
Connected component in undirected graph

Day 8 （9/17）
做了两题mock interview里的

day 15
Two Sum III - Data structure design 简单题也没能轻轻松松写出来- =，还是需要继续磨练基本功啊
Evaluate Reverse Polish Notation 这个轻松写过

# Day_18

水两道LL
Linked List Cycle
Intersection of Two Linked Lists

# Day 2:

* 839. Similar String Groups: Union Find
* 231. Power of Two

Stage II : 分类各个击破
day12-09/18-one day for binary tree
binary tree
1. 107. Binary Tree Level Order Traversal II
2. 106. Construct Binary Tree from Inorder and Postorder Traversal
3. 103. Binary Tree Zigzag Level Order Traversal
4. 111. Minimum Depth of Binary Tree
5. 110. Balanced Binary Tree
6. 98. Validate Binary Search Tree
7. 114. Flatten Binary Tree to Linked List
8. 236. Lowest Common Ancestor of a Binary Tree
9. 298. Binary Tree Longest Consecutive Sequence
10. 99. Recover Binary Search Tree
11. 222. Count Complete Tree Nodes
12. 105. Construct Binary Tree from Preorder and Inorder Traversal
13. 106. Construct Binary Tree from Inorder and Postorder Traversal
14. 96. Unique Binary Search Trees

day 14
今天两题
All O`one Data Structure 昨天写了这题怎么都de不出来一个bug，今天什么都没改交了发现过了还打败了98%多……leetcode太迷了
Can Place Flowers

Day 8 （9/17）
490 505