HashTable

• Group Anagram 49

sorted(bca) -> abc || keys = [0,1,0....0], len(keys) = 26

• Ads Converation Rate
• TargetSum

LinkedList

• Reverse Linked List 206
• Clone LinkedList with Random Pointer 138
• FlattenBinaryTreetoLinkedList 114

Array

• Partition Labels 763
• Missing Number
• ContinuousSubarraySum

two pointer

• FindMissingNumberFromArithmeticSequence TBR

Heap

• Meeting Room 254

Arrays.sort(intervals, new Comparator<int[]>(){ public int compare(){}})

• Top K Frequent Elements 347
• Merge K LinkedList 23

Input can be a streaming of data (access with get() method) instead of a list, or divide & conquer

• Median from Data Stream 295

Stack

• ValidParentheses 20

921, 1514 minimum inserts to make valid (), stack or one pass sol

• TrappingRainWater 42
• LargestRectInHistogram 84

42 & 84, care about condition of pushing to stack

• DailyTemperature 739
• RemoveDuplicateLetters(TBD) 316

Tree

• BalancedBinaryTree 110
• BoundaryOfBinaryTree 545
• FlattenBTtoLinkedList 114
• FindCommonAncestorOfBinaryTree 235 236

BST -> BT -> N-ary Tree

DFS

• DividedToGroups
• Number of Distinct Islands 694
• Maximal Square 221

694-221

• Pacific Atlantic Waterflow
• GraphValidTree
• MinimumHeightTree

TLE, tree dp + purning TBF, undirected graph

• Course Schedule 207
• Path from Source to Dest 1059

DAG, states: {unvisted, visiting, visited}

• Reconstruct Itinerary 322

DAG

• Find Leaves of Binary Tree 366
• All Paths from Source to Target 797
• Number of Island, Largest Path

BFS

• BinaryTreeRightSideView 199
• WordLadder
• Shortest Distance from All Buildings
• Shortest Path with Obstacle Elimination
• Amazon Locker
• Alien Dictionary

BFS in DAG, Toposort, course schedule emmm

Backtracking

• CombinationSum 39 40 216

sorted or not, res[:] or res

DP

• RodCutting
• CoinChange
• LongestPalindromicSubstring
• LongestContinuousCommonSubArray

dp[i,j]: LCCA of A[:i] and B[:j],  dp[i,j] = dp[i + 1][j + 1] + 1 if A[i] == B[j]

• LongestIncreasingSubsequence 300

dp[i,j]: LISS of nums[i:j], dp[j] = max(dp[j], dp[i] + 1) if nums[i] < nums[j]

• LongestCommonSubsequence 1143

• LongestStringChain 1048

• WordBreak 139 140

dp[i]: s[:i] is workbreakable, dp[j] = dp[i]   if A[i:j] in wordDict, 140 TLE

• Edit Distance 72

dp[i,j]: number of operations from wordA[:i] to wordB[j:].  dp[i][j] = dp[i - 1][j - 1] if wordA[i] == wordB[j], dp[i][j] = 1 + max(insert, delete, swap)  

• Matrix Chain Manipulation

Algorithms

• Fisher-Yates Shuffle

If it's how random.shuffle() implemented

• Floyd's Cycle Detection
• Garbage Collection in Java
• QuickSort
• KMP TBR
• BinarySearch
• MergeSort
• CountSort
• FuzzySort

Divide & Conquer

• Closest points

Bit Manipulation

• Power of 4

OOD

• Queen's Gambit'
• LRU Cache
• Random Number Generator
• Median from Data Stream 295
• Top K Frequent from Data Stream
• ParkingLot
• Java Interface & Abstract class
• Templates
• Functor

System Design

• Tiny URL

Security

• Devil Pointer

Vim

Key Bindings | Pattern

Jump based on relativenumber | <number><direction>
Visual mode: 5j(jump down 5 lines), 3i(jump up 3 lines), very helpful when enable 'set relativenumber', (no ruler plz)

Execute program within editor | <shift> + ':' + '!' + <command>
Sometimes I need to :wq and run some program and go back to editor, but !<command> helps run program within vim. If <command> is empty, :! will simply run last command

Comment / Uncomment multiple lines
<control> + v: enter visual mode, <esc> + v may not work, it will select blocks of lines instead of first column in the next step
Select the lines that you want to comment / uncomment
Comment: <shift> + i: Enter the insertion mode, type the comment sign: #, // etc. Then <ESC>
Uncomment: d

Navigate between file structure and file content
vim . in current directory
:NERDTree
<control> + w(double click) to navigate between windows 

Userful Plugins:

gmarik/Vundle.vim: Best package manager for lazy people(maybe?)
preservim/nerdtree: File structure and menu bar
Valloric/YouCompleteMe: Finally works in macos 10.14 
zxqfl/tabnine-vim: Neural Network + YouCompleteMe, but slows vim down
morhetz/gruvbox: Best color scheme for py i guess? not suitable for cpp though

BGM

• Marasy Playlist
• [Gurenge Animenzzz] (https://www.youtube.com/watch?v=NQMmZ4Psb7w)
• You Lie in April
• Shining/Snow-Rain
• Lemon
• からくりピエロ
• Karakuri Pierrot
• BigYear
• Unravel
• Sik-K
• Guren no Yumiya
• Never Grow Up
• YOASOBI
• Goose House (Uncle A)
• Ignite
• Angel
• Sanbonezakura
• Loser
• Honey
• Way back home
• Lemon
• Brave Heart
• Light of the Seven
• Anime OP Combo
• AOA OP Combo