8月刷题/Mock interview接龙活动（缺米刷题的来）

每日一题居然都做了这么久哎

8月第一次
1.         Reverse Words in a String
2.         Validate IP Address
3.    Decode Ways
4.    K Closest Points to Origin        (both heap and quick select)
5.    Third Maximum Number       

小bug还挺多，看来还是要写好了在submit

8.3打卡第二天
做了5题，分别针对prefix sum和two pointer
（1）求subarray, continuous subarray, substring要联想到prefix sum
（2）数飞机，用差分前缀和
（3）heaters这题可以先两个数组排序，然后二分搜索找前面最近的，后面最近的，比谁更近，维护一个max radius
（4）书店问题，搞清sliding window里维护的是什么，left right移动时对window里面状态的影响
file:///Users/minmao/Desktop/Screen%20Shot%202020-08-04%20at%2012.08.30%20AM.png

day 1 打卡sliding window

Longest Substring Without Repeating Characters   5 hours, 12 minutes ago
Wrong AnswerjavaLongest Substring Without Repeating Characters   5 hours, 12 minutes ago
AcceptedjavaMinimum Number of K Consecutive Bit Flips   5 hours, 14 minutes ago
Wrong AnswerjavaMinimum Number of K Consecutive Bit Flips   5 hours, 14 minutes ago
Wrong AnswerjavaMinimum Number of K Consecutive Bit Flips   5 hours, 17 minutes ago
AcceptedjavaStatistics from a Large Sample   8 hours, 45 minutes ago
AcceptedjavaFind Median from Data Stream   9 hours, 1 minute ago
AcceptedjavaSliding Window Median   9 hours, 21 minutes ago
AcceptedjavaSliding Window Median   9 hours, 27 minutes ago
AcceptedjavaSliding Window Median   9 hours, 35 minutes ago
Wrong AnswerjavaSliding Window Median   9 hours, 36 minutes ago
Wrong AnswerjavaSliding Window Median   9 hours, 38 minutes ago
Wrong AnswerjavaSliding Window Median   9 hours, 39 minutes ago
Wrong AnswerjavaSliding Window Median   9 hours, 39 minutes ago
Wrong AnswerjavaSliding Window Median   9 hours, 40 minutes ago
Wrong AnswerjavaSliding Window Median   9 hours, 41 minutes ago
AcceptedjavaSliding Window Maximum   10 hours, 55 minutes ago
AcceptedjavaSliding Window Maximum   11 hours, 7 minutes ago
Compile ErrorjavaSliding Window Maximum   11 hours, 7 minutes ago
Wrong AnswerjavaSliding Window Maximum   11 hours, 9 minutes ago

Day 42, solved 1 problem.

Tip: Use API or count the upper cases.

2020.8.4打卡，leetcode 207, 756, 332, 725

65 Valid Number

这道题刷新了我对double的认知…
我不知道
10.
.1
+.8
46.e3
都是合理的

梳理一下各种限制条件
1. 0-9
2. e 只能出现一次，后面可以是-+和数字，不能在结尾，后面不能有小数点
3. . 只能出现一次，可以在结尾，之前要跟数字
4. -+: 只可以在开头，或者e之后出现

其他
1. White space
2. alphabetic

71 Simplify Path

Corner case
/…
误以为directory只能是alphabetic

这种if else循环判断的题目，要先想好条件再code

3种情况
1、 / ， 没有意义，但是是重要的隔断判断依据
2、 .., ../ 这是back, 只在前面有一个地址的时候，不然没影响
3、 ./, . 没有意义，但是要和directory name区分开
4、 directory name


faster than 5.24%, 非常慢，需要优化一下
String[] components = path.split("/");
for (String directory : components) {
Using stack

Time Complexity: O(N)
Space Complexity: O(N)

62、63、64 Unique Paths，Unique Paths ||， Minimum Path Sum

DP练习
Recursion练习
Recursion with Memorization

8.4 打卡

684 Redundant Connection
685 Redundant Connection II
1319 Numbers of Operations to Make Network Connected

Day 1, 2道

check for today