[第二期活动] 在职刷题打卡，目标工作日一天2题，周末一天5题

day 3

Review BFS shortest path part
1. Binary Tree Maximum Path Sum 2. Cheapest Flights Within K Stops

Design
Review consistence hash & CAP

#Day_07

Finished * 2:
62. Unique Paths
647. Palindromic Substrings, 这次是DP解的，mark一下下次看看其它解法

day 6
Binary Watch 一个并不简单的简单题
Serialize and Deserialize Binary Tree 一个并不hard的hard题。。。bfs水过

day 4

水了一天 周四上完班太累了
subset I / II
permutation I / II

Day 4
Bit Manipulation CTCI Questions
蠡口 Trap Water 硬拼了一个蠡口 LRU Cache 水

#Day_08

Finished * 2:
32. Longest Valid Parentheses
123. Best Time to Buy and Sell Stock III

最近要找时间狂看系统设计了

#Day_1

Finish * 2
1. Binary Tree Zigzag Level Order Traversal
2. Prison cells after N days

day 7，3题
reverse Words in a String II
reverse Words in a String I
Rotate Array

#Day_09

Finished * 5
336. Palindrome Pairs, empty string checking is beyond annoying.
243. Shortest Word Distance
244. Shortest Word Distance II
207. Course Schedule
210. Course Schedule II, 这几天做点graph相关的，好多都忘记了

读了System Design Interview - An insider's guide p15 ~ p45，主要讲了如何horizontally和vertically进行System Scaling，学习了Cache Tier (CDN, cache), Stateless Tier (NoSQL), Multiple Data Centers, Sharding/Resharding Data, Decoupling (Message Queue), Tools (Logging, Metrics, Monitoring, Automation)等帮助容纳更多同接users的techniques，虽然很怀疑3D Graphics岗的面试会问这些偏分布式和网络的内容，但明后天还是打算把剩下50页讲系统设计题目的看完。

Day 5
1. gcd of strings
2. merge arrays and lists

Day 7
1. all two sum related questions (1, 170, 653, 1099, 15, 16, 259, 611, 18, 454)
  => Two pointer / Hash / Binary search
  => ksum reduce to 2sum
2. 560, prefix sum