Software Engineering

Overview

• Coding
• Algorithm
  • Complexity
  • Sorting
  • Graph Algorithm
    • BFS/DFS
    • Dijkstra algorithm
    • BFS and Dijkstra
    • Dijkstra and Floyd Warshall
  • SSSP and DP
    • topological sort
    • Bipartition
    • Cycle find problems
    • MST
    • SSSP(Single-Source Shortest Paths)
    • APSP(All-Pairs Shortest Paths)
    • Minimum Weight Cycle in an Undirected Graph
    • Some relatively hard graph problems
  • Dynamic Programming
    • Summary
    • Classical and its variations
    • Find Recurrence in DP
    • 1D DP
    • 2D DP
    • 3D DP
    • 4D DP
    • Top Down DP and Bottom Up DP
    • States of the DP is the Key
    • DP programs on the grid
  • State machine DP
    • Range DP
  • DP look backwards
  • Digit DP
    • TSP
    • Bitmask DP
    • DP and combinations
• Bit Manipulation
• Sting and bit manipulation
• Priority Queue
• Monotonic Stack/Queue
• Two Pointers
• Two Pointer and Monotonic Queue and Greedy
• Slow and fast pointer
• Binary Search
• String problems
• Union find
• Segment Tree
• Rolling hash
• Binary Lifting Algorithm
• Simulated annealing
• Bit manipulation
• Backtracking
• Backtrack and bitmask
• Process simulation
• Discuss by cases
• Count on 1D/2D array
• Power, Binary Exponentiation and Matrix Exponentiation
• Minimum/maximum distance to points
• Game theory
• Stone Games
• submatrix problems
• Mixed algorithms
  • BFS and Dijkstra
  • BFS/Dijkstra/DP
  • DFS and Binary Search
  • DFS and pre/post order traversal and two pointer
  • 2D range sum and DP and multi-source 0 1 bfs
  • Topological sort, cycle finding in directed graph and DFS
  • Topological sort and DP
  • Backtracking and Math
  • Union find and binary search
  • Prefix sum and edge cases
  • Prefix sum and bit manipulation
  • Soft deletion and Monotonic Queue
  • DP and binary seach and monotonic queue
  • DFS and DP
  • Two pointers and linked list
  • Two pointers and binary search
  • Union Find and two pointer
  • Union Find, DFS/BFS
  • String problems by using C++
  • Limited Space problems
• Arrays
• Stack
• Sparse Table or Stack
• Stack and binary tree
• rectangle area
• Geometric Problems
• Interval Problems
• Word search problems
• Solve the problem backwards or reversely
• Preprocess to speed up the computation
• Data Structure
  • Data Structure Design
  • Heap
  • Multiset
  • Linked List
  • Binary Tree
  • Tree
  • Bit manipulation and Tree
  • Trie
  • Trie and Fast Walsh-Hadamard transform algorithm
  • Fenwick Tree or binary index tree
  • Red Black Tree
  • ODT(Old Driver Tree)
  • Soft deletion
• Games
• Greedy construction
• Edge cases
• Parentheses problems
• Permutations and combinations
• Prefix sum or prefix frequency sum
• Meet in middle
• Math
• Random topics
  • My Mistakes
  • Garbage Collection
• Source Code understanding
  • Linux Source Code
• Kernel Programming
• Operating system
  • Memory allocation
• STL source code
• Python tips
• C++ STL
• C++ tips
• Haskell
• Rust
• Git tips
• Docker
• Imporant times
• Go language
  • Basic
  • Advanced
• Top Coders and cool blogs
• SWE related
• Hardwares
  • Edge devices
• Tools
  • Vim
• Real life problems

Coding

My ‘Serious’ coding got started since I became a student as a Computer Science Major at the CUNY. Thanks for Dr. Siyu Liao’s help during my earlier programming life. Thanks for Professor Liang Huang to guide me to the Python world. I am actively participate in the Leetcode weekly contest and you can find my profile here.

Algorithm

Complexity

• Nice visualization for computation complexity

Sorting

• Sorting algorithms
• quicksort
• Leetcode 274 H index
• Kth
• merge sort on a linked list

Graph Algorithm

BFS/DFS

• LeetCode 1462 Course Schedule IV
• Leetcode 797. All Paths From Source to Target
• A standard BFS Leetcode 773 Sliding Puzzle
• C++ DFS Leetcode 490. The Maze
• Jump Game IV
• Word Ladder II: BFS
• Using BFS to solve a hard problem

Dijkstra algorithm

• Correctness of Dijkstra algorithm
• An interesting problem solved by dijkstra algorithm: LC 882. Reachable Nodes In Subdivided Graph

  BFS and Dijkstra

• BFS + Dijkstra

Dijkstra and Floyd Warshall

• Dijkstra and Floyd Warshall

SSSP and DP

• SSSP + DP -From backtracking to SSSP to DP

topological sort

• LeetCode course schedule
• An interesting topological sort algorithm

Bipartition

• Leetcode 886. Possible Bipartition

Cycle find problems

• Cycle find algorithm: Leetcode 1559. Detect Cycles in 2D Grid
• Find the minimum weight cycle in an undirected graph

MST

• Minimum Spanning Tree
• MST: 1584. Min Cost to Connect All Points

SSSP(Single-Source Shortest Paths)

• SSSP on Unweighted Graph
• SSSP on Weighted Graph
• Dijkstra
• Best video to explain dijkstra algorithm
• Build the shortest path spanning tree
• Solve the Second Shortest Path problem
• SSSP on Graph with Negative Weight Cycle

  APSP(All-Pairs Shortest Paths)

Minimum Weight Cycle in an Undirected Graph

• minimum weight cycle in an undirected graph

Some relatively hard graph problems

• Hard graph 1
• Hard graph 2

Dynamic Programming

Summary

• Summary
• DP types

Classical and its variations

• Longest Increasing subsequence
• Variations of LIS probems
• Mountain Array and LIS
• LIS:1626. Best Team With No Conflicts
• [LIS ACwing] (https://jimmy-shen.medium.com/lis-4de7641509a0)
• Longest common subsequence
• LCS and LIS: LC 1713 Minimum Operations to Make a Subsequence
• LIS: minimum operations to make the array K-increasing
• Longest Palindromic Subsequence
• Combination sum or Coin Change
• Jump Games
• knapsack problem
• [Knapsack problems ACWing] (https://jimmy-shen.medium.com/knapsack-problem-26634d6a98a8)
• a knapsack problem:leetcode 1621. Number of Sets of K Non-Overlapping Line Segments
• A DP problem solved by using a Knapsack problem way 1639. Number of Ways to Form a Target String Given a Dictionary
• Rod Cutting
• House Robber II

Find Recurrence in DP

• Find Recurrence in DP

1D DP

• LeetCode 55 Jump Game
• A DP problem
• Leetcode 983. Minimum Cost For Tickets

2D DP

• 2d dp
• 2D range sum
• LCS style problems
• LeetCode 1563. Stone Game V

3D DP

• 3d dp
• Dijkstra and Floyd Warshall
• A 3D DP problem
• A 3D DP problem 1463. Cherry Pickup II

4D DP

• 4D DP

Top Down DP and Bottom Up DP

• a case of top down is faster than bottom up

States of the DP is the Key

• DP leetcode 903. Valid Permutations for DI Sequence

DP programs on the grid

• DP problems on the grid

State machine DP

• DP State Machine

Range DP

• Range DP
• Greedy is wrong and DP is correct: LC 1547. Minimum Cost to Cut a Stick
• Range DP

DP look backwards

• DP Look backwards LC 1871. Jump Game VII

Digit DP

• Digit DP

TSP

• Are you ready for solving the traveling salesman problem?

Bitmask DP

• bitmask DP -LC 1900. The Earliest and Latest Rounds Where Players Compete

  DP and combinations

• DP related to combination LC 1866. Number of Ways to Rearrange Sticks With K Sticks Visible

Bit Manipulation

• Bit Manipulation
• LeetCode 342 Power of Four
• LeetCode 137 single number ii
• LeetCode 260 single number iii
• XOR: LC 1734. Decode XORed Permutation
• Using bit manipulation to speed up the computation LC 1178 Number of Valid Words for Each Puzzle

Sting and bit manipulation

• String and bit manipulation

Priority Queue

• priority queue and greedy algorithm
• Leetcode 1792. Maximum Average Pass Ratio

Monotonic Stack/Queue

• Monotonic queue
• Sliding window min/max, priority queue & Monotonic Queue
• 2d sliding window min/max problem
• 713. Subarray Product Less Than K
• Monotonic queue: LC933 Number of Recent Calls
• Monotonic Queue 1696 jump game VI
• LC Largest Rectangle in histogram
• Using monotonic stack to solve some problems
• 1944. Number of Visible People in a Queue

Two Pointers

• Two Pointer problems
• Two Pointer
• 3sum
• Advanced two pointer problem: LC 1847 Closest room
• Two pointers and sliding window
• Such a nice two pointer problem
• A nice two pointer problem
• A nice two pointer problem LC 151. Reverse Words in a String
• Two slow and one fast pointer: LC 142 Linked list cycle II

Two Pointer and Monotonic Queue and Greedy

• Two Pointer and Monotonic Queue and Greedy
• MUSTSEE Two Pointer and Deque

Slow and fast pointer

• slow and fast pointer

Binary Search

• binary search
• How to set the middle value in a binary search
• Why binary search is not working in this problem
• A hard binary search problem find median of two sorted array
• 1760. Minimum Limit of Balls in a Bag
• A harder bianry search problem 658. Find K Closest Elements
• Two layer binary search

String problems

• KMP
• String
• Hard string

Union find

• Union find
• Leetcode 1562. Find Latest Group of Size M
• Use union find to solve a hard problem: LC:2076. Process Restricted Friend Requests
• Union Find and Prime Factorization 952. Largest Component Size by Common Factor
• The hardest union find problem ever

Segment Tree

• segment tree and RMQ

Rolling hash

• rolling hash

Binary Lifting Algorithm

• Binary Lifting Algorithm

Simulated annealing

• Simulated Annealing

Bit manipulation

• Bit manipulation
• Subsets

Backtracking

• Backtracking 1
• Backtracking 2
• Backtracking 3 40. Combination Sum II
• Using backtrack to solve the Word Search problem
• word search, trie and backtrack

  Backtrack and bitmask

• Backtrack by using bit mask to record visited node
• Backtrack and bit manipulation

Process simulation

• process simulation
• Solve the problem by simulating the whole process
• Hack a LC hard problem step by step

Discuss by cases

• LCP 29 band locations

Count on 1D/2D array

• count on 1D/2D array

Power, Binary Exponentiation and Matrix Exponentiation

• Power, Binary Exponentiation and Matrix Exponentiation -Leetcode 1808. Maximize Number of Nice Divisors

Minimum/maximum distance to points

• Minimum/maximum distance to points

Game theory

• Game theory stone game

Stone Games

• Stone Game VI and VII

submatrix problems

-LeetCode 1727. Largest Submatrix With Rearrangements

Mixed algorithms

BFS and Dijkstra

• BFS and Dijkstra algorithm

  BFS/Dijkstra/DP

• Leetcode 1824. Minimum Sideway Jumps(MUSTSEE)

DFS and Binary Search

• DFS and Binary Search

DFS and pre/post order traversal and two pointer

• A tree problem: Special Nodes MUSTSEE

2D range sum and DP and multi-source 0 1 bfs

Topological sort, cycle finding in directed graph and DFS

• Topological sort, cycle finding in directed graph and DFS with memo:LeetCode 1857. Largest Color Value in a Directed Graph

Topological sort and DP

• Topological sort and DP
• Topological sort and DP 2

  Backtracking and Math

• Backtracking and graph Leetcode 1766. Tree of Coprimes

Union find and binary search

• Union find and binary search

Prefix sum and edge cases

• Prefix sum and edge cases
• Super prefixsum

Prefix sum and bit manipulation

• Prefix sum and bit manipulation

Soft deletion and Monotonic Queue

• 2d sliding window min/max problem

DP and binary seach and monotonic queue

• DP, binary seach and monotonic queue
• DP an dbinary search

DFS and DP

• DFS and DP

Two pointers and linked list

• Two pointers and Linked List

Two pointers and binary search

• two pointer and binary search
• Two pointer and binary search Leetcode 76 Minimum Window Substring -Binary search and two pointers: LeetCode 76. Minimum Window Substring

Union Find and two pointer

• union find and two pointers LC 1697. Checking Existence of Edge Length Limited Paths

Union Find, DFS/BFS

• union find, DFS/BFS

String problems by using C++

• String problems in C++

Limited Space problems

• O(1) space or inplace

Arrays

• arrays problems

Stack

• Using stack to solve the Parentheses problems
• Stack: LeetCode 316 remove duplicate letters
• LC: 1717 maximum score from removing substrings

  Sparse Table or Stack

• Sparse Table or Stack?
• MUSTSEE LC150. Evaluate Reverse Polish Notation

Stack and binary tree

-stack and binary tree: LC 150 Evaluate Reverse Polish Notation

rectangle area

• 2D range sum, Kadane’s algorithm and maximum subarray sum no more than k
• Rectangle Areas: Coordinate Compression

Geometric Problems

• Geometric problems
• Polygon collision
• The intersection of Convex Polygons Algorithm
• Max Points on a Line

Interval Problems

• Interval problems
• LeetCode: 1288. Remove Covered Intervals

Word search problems

• Backtracking for words related problems

Solve the problem backwards or reversely

• Solve the problem backwards
• Transform the problem to a more solvable one
• Think the problem reversely -BFS and solve the problem reversely

Preprocess to speed up the computation

-LC 1761. Minimum Degree of a Connected Trio in a Graph

Data Structure

Data Structure Design

• Hash table in python
• A comprehensive one about how to implement a hash table
• Why use a prime number as the hash table size
• LRU and LFU
• Min Stack or Max Stack
• First Unique Number
• 1622. Fancy Sequence

Heap

• Implement a heap
• Implement a binary heap by C++
• Dynamically building the heap

Multiset

• using 3 multiset MUSTSEE

Linked List

• Singly Linked List
• List
• linked List: Leetcode 24. Swap Nodes in Pairs
• Linked List Problems

Binary Tree

• Basic binary tree problems
• MUSTSEE super binary tree template problems
• Advanced binary tree problems
• binary tree maximum path sum
• Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree
• BFS and binary tree
• LeetCode 430. Flatten a Multilevel Doubly Linked List
• Catalan number and Unique Binary Search Trees
• LeetCode 449 serialize and deserialize BST
• MUSTSEE LeetCode 426. Convert Binary Search Tree to Sorted Doubly Linked List
• LCA in a tree
• MUSTSEE LeetCode 814 Binary Tree Pruning

Tree

• Tree problem
• Diameter of a tree

Bit manipulation and Tree

• Bit manipulation and diameter of a tree

Trie

• Trie
• Trie in C++
• Trie
• Trie and XOR
• Trie and DFS

Trie and Fast Walsh-Hadamard transform algorithm

• Trie and Fast Walsh–Hadamard transform algorithm

Fenwick Tree or binary index tree

• Fenwick Tree or binary index tree

Red Black Tree

• Red Black Tree

ODT(Old Driver Tree)

• ODT

Soft deletion

• soft deletion problems

Games

• LeetCode 913. Cat and Mouse
• Games

Greedy construction

• Queue reconstruction by height

Edge cases

• Edge cases problems

Parentheses problems

• Parentheses problems

Permutations and combinations

• Permutations
• Leetcode 484 Find Permutation

Prefix sum or prefix frequency sum

• 1+1/2+1/3+1/4…1/n = log n LC 1862. Sum of Floored Pairs

Meet in middle

• C++ meet in middle

Math

• MUSTSEE three formulas for algorithm complexity analysis

Random topics

My Mistakes

• My Mistakes

Garbage Collection

• Garbage Collection

Source Code understanding

Linux Source Code

Kernel Programming

• Hello World Kernal Programming

Operating system

Memory allocation

• stack and heap

STL source code

• Where to find STL source code

Python tips

• Format python code
• Python testing
• What is the current path when python import module?
• All you need to know about Python Type Hints
• Python floating number sum give different result
• Exploration of the blog “Why Python is Slow: Looking Under the Hood”

C++ STL

-STL Containers

C++ tips

• Customized comparison in C++ part 1
• Customized comparison in C++ part 2
• STL map/unordered_map with a Vector for the Key
• Lambdas in C++ tutorial
• C++ auto
• lambdas in c++
• C++ Tips
• C++ Should curly braces be on their own line or not?
• Computations Modulo P in C++
• set_intersection in C++
• for_each in C++
• C++ sort by tuple or by pair
• C++ sort by word length
• C++ function within a function
• Format C++ code to google coding style
• 0x3f3f3f
• C++ websites and books
• Vector emplace_back struct c++
• Difference between vector and stack in C++
• Have a set of structs
• [Why does priority queue (max heap) in C++ use less instead of greater?](https://jimmy-shen.medium.com/why-does-priority-queue-max-heap-in-c-use-less-t-instead-of-greater-t-f1b78c3a04b2)

Haskell

• Why Haskell and How to Learn?

Rust

• Rust on MAC from beginning

Git tips

• Git tips
• git merge VS git rebase
• Tutorials of Git and Git internal

Docker

• Docker
• How to use Docker
• Update docker containers’ default storage location on Ubuntu

Imporant times

• Solve a thousand problems

Go language

Basic

• Go ‘:=’ vs ‘=’
• Interesting things in Go language
• Goroutines
• Json and Go
• struct tags in GO
• Go tips
• Channels in GO
• Go and OOP
• Golang Packages
• Golang Glog
• Golang Random number generator

Advanced

• Golang and Pointer
• Map in Golang
• Array, Slice and String in Golang
• How to install gocv on mac
• Slice of struct or slice of pointer to a struct
• Golang nested struct
• Golang and protocol buffer

Top Coders and cool blogs

• top coders
• Cool blogs

SWE related

• Programmer’s hardest tasks

Hardwares

Edge devices

• Raspberry Pi 4

Tools

Vim

• Vim and Python

Real life problems

• iPhone Storage Full, Stuck on home screen