[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_12 (8/24)

Rectangle overlap
Window sum
Course schedule II
High five
K closest Point

#Day_24

Finished * 2 水两道
Find Common Characters
Maximum Subarray

打卡Day 6

289. Game of Life - Easy O(m*n) space solution. Could be optimized to O(1) space by marking previous states. Two follow ups: 1) For large sparse matrix, we could only store locations of live cells. 2) For very large matrix that may not fit into memory, we could process only 3 rows of matrix at one time and discard previous rows as we go.
57. Insert Interval - O(n) greedy solution.
253. Meeting Rooms II - Using priority queue
387. First Unique Character in a String - Easy hash map
383. Ransom Note - Easy hash map
186. Reverse Words in a String II

Day_13 (8/25)

Decrease to be palindrome
Add digits
Subarray product less than K
Minimum size subarray sum
Palindromic substrings

#day_10

Review
3. longest-substring-without-repeating-characters

New
923.3-sum-with-multiplicity

#Day_25

三题，水一题
Consecutive Numbers Sum
Asteroid Collision
Reverse Linked List

打卡Day 7

345. Reverse Vowels of a String
205. Isomorphic Strings
293. Flip Game
294. Flip Game II - Optimized using cache
290. Word Pattern - Very similar to 205
249. Group Shifted Strings - Using relative distances between characters as keys
87. Scramble String - Recursion with Memo (DP)
358. Rearrange String k Distance Apart - Greedy + Priority Queue - Similar to problem 621. Task Scheduler
316. Remove Duplicate Letters - The difficult part is recognizing that it could be solved using greedy/mono-stack.

Day_14 (8/26)

Word Ladder II
One edit distance

day 23
Binary Tree Longest Consecutive Sequence
Sum Root to Leaf Numbers

#Day_11

Review:
559.Maximum Depth of n-ary tree
334. Reverse String
12. Integer To Roman
200. Number of Islands