Owner: Brandon Peebles Image from https://www.clipartkey.com/view/ohhmhm_computer-science-and-engineering-computer-science-icon-circle/
This living document is my study plan for computer science and software engineering topics. Given my previous experience in analytics/operations plus education in industrial & systems engineering, it’s been tailored to specifically fill my own knowledge gaps and prepare me for a role in software engineering. It outlines what I’m covering (in roughly the order I plan to cover it) as well as serves as a way to track my progress. I will be focusing on core computer science topics/concepts, full-stack JavaScript web development, and Python.
- Harvard CS50x: Introduction to Computer Science link
- freeCodeCamp (my Full Stack development certification)
- Responsive Web Design
- JavaScript Algorithms and Data Structures
- Front End Libraries (Bootstrap, jQuery, Sass, React, Redux)
- Data Visualization (D3, JSON APIs and Ajax)
- APIs and Microservices (Npm, Node, Express, MongoDB, Mongoose)
- Information Security and Quality Assurance (HelmetJS, QA and Testing with Chai, Advanced Node & Express)
- Overview of Operating Systems:
- Overview of Computer Processing & Architecture:
- Crash Course: Computer Science - 41 videos: (in progress) Really great overview video series about computer science history, computer architecture, languages, internet, and more.
- Data Structures & Algorithms: (in progress) Combined study using the following resources
- Data Structures & Algorithms in Python (book)
- Data Structures & Algorithms in Python (course)
- Coding Interview University: Learn and practice implementations of the following. Outline presented --> see detailed view in appendix below, adapted from the Coding Interview University repo created by John Washam (link)
- Algorithmic Complexity / Big-O / Asymptotic Analysis
- Basic Data Structures
- Arrays
- Linked Lists
- Stack
- Queue
- Hash tables
- Binary Search
- Bitwise Operations
- Trees
- General knowledge & Background
- Binary Search Trees: BSTs
- Heap / Prioritity Queue / Binary Heap
- Balanced Search Trees (general concept + implementation of method to check if it is balanced)
- Traversals: preorder, inorder, postorder, BFS, DFS
- Sorting
- Selection
- Insertion
- Heapsort
- Quicksort
- Merge sort
- Graphs
- Directed
- Undirected
- Adjacency Matrix
- Adjacency List
- Traversals: BFS, DFS
- Other Topics (when I have time): Outline presented --> see detailed view in appendix below, adapted from the Coding Interview University repo created by John Washam (link)
- Recursion
- Dynamic Programming
- Combinatorics (n choose k) & Probability
- NP, NP-Complete and Approximation Algorithms
- Testing
- Scheduling
- String searching & manipulation
- Tries
- Floating Point Numbers
- Unicode
- Endianness
- Networking
- Compilers
- Emacs and vi(m)
- Unix command line tools (read book in Other Resources)
- Messaging, Serialization, and Qeueing Systems
- Flask Web Development 2nd Edition (book) (TBD - may prioritize Node.JS instead)
- Clean Code (book)
- Cracking the Coding Interview 6th Edition (book)
- Overview of Discrete Mathematics:
- Introductory Discrete Mathematics (book) - read for general knowledge
- [Intro to Discrete Math - 79 videos to watch for general knowledge] (https://www.youtube.com/watch?v=rdXw7Ps9vxc&list=PLHXZ9OQGMqxersk8fUxiUMSIx0DBqsKZS)
- Books
- Learning Python: Powerful Object Oriented Programming 5th Edition
- The UNIX Programming Environment
- The C Programming Language 2nd Edition
- Cracking the Coding Interview 6th Edition
- Websites
- LeetCode (link)
- OSSU: Computer Science (repo)
- Teach Yourself Computer Science
First section is again adapted directly from the Coding Interview University repo created by John Washam (link). I've included it below so I can check things off as I go.
- Nothing to implement
- There are a lot of videos here. Just watch enough until you understand it. You can always come back and review.
- If some of the lectures are too mathy, you can jump down to the bottom and watch the discrete mathematics videos to get the background knowledge.
- Introductory Discrete Mathematics (book)- quick review of set theory/logic + sections on analysis of algorithms
- Harvard CS50 - Asymptotic Notation (video)
- Big O Notations (general quick tutorial) (video)
- Big O Notation (and Omega and Theta) - best mathematical explanation (video)
- Skiena:
- UC Berkeley Big O (video)
- UC Berkeley Big Omega (video)
- Amortized Analysis (video)
- TopCoder (includes recurrence relations and master theorem):
- Cheat sheet
-
- Implement an automatically resizing vector.
- Description:
- Implement a vector/dynamic array class (mutable array with automatic resizing):
- size() - number of items
- capacity() - number of items it can hold
- at(index) - returns item at given index, blows up if index out of bounds
- push(item)
- insert(index, item) - inserts item at index, shifts that index's value and trailing elements to the right
- prepend(item) - can use insert above at index 0
- pop() - remove from end, return value
- delete(index) - delete item at index, shifting all trailing elements left
- remove(item) - looks for value and removes index holding it (even if in multiple places)
- find(item) - looks for value and returns first index with that value, -1 if not found
- resize(new_capacity) // private function
- when you reach capacity, resize to double the size
- when popping an item, if size is 1/4 of capacity, resize to half
- Time
- O(1) to add/remove at end (amortized for allocations for more space), index, or update
- O(n) to insert/remove elsewhere
- Space
- contiguous in memory, so proximity helps performance
- space needed = (array capacity, which is >= n) * size of item, but even if 2n, still O(n)
-
- General concept via textbook
- Linked List vs Arrays:
- implement:
- size() - returns number of data elements in list
- empty() - bool returns true if empty
- value_at(index) - returns the value of the nth item (starting at 0 for first)
- push_front(value) - adds an item to the front of the list
- pop_front() - remove front item and return its value
- push_back(value) - adds an item at the end
- pop_back() - removes end item and returns its value
- front() - get value of front item
- back() - get value of end item
- insert(index, value) - insert value at index, so current item at that index is pointed to by new item at index
- erase(index) - removes node at given index
- value_n_from_end(n) - returns the value of the node at nth position from the end of the list
- reverse() - reverses the list
- remove_value(value) - removes the first item in the list with this value
- Doubly-linked List
- Description (video)
- No need to implement
-
- Stacks (video)
- Using Stacks Last-In First-Out (video)
- Will not implement. Implementing with array is trivial.
-
- Implement using linked-list, with tail pointer:
- enqueue(value) - adds value at position at tail
- dequeue() - returns value and removes least recently added element (front)
- empty()
- Implement using fixed-sized array:
- enqueue(value) - adds item at end of available storage
- dequeue() - returns value and removes least recently added element
- empty()
- full()
- Cost:
- a bad implementation using linked list where you enqueue at head and dequeue at tail would be O(n) because you'd need the next to last element, causing a full traversal each dequeue
- enqueue: O(1) (amortized, linked list and array [probing])
- dequeue: O(1) (linked list and array)
- empty: O(1) (linked list and array)
- Implement using linked-list, with tail pointer:
-
-
Videos:
-
Online Courses:
-
implement with array using linear probing
- hash(k, m) - m is size of hash table
- add(key, value) - if key already exists, update value
- exists(key)
- get(key)
- remove(key)
-
-
- Binary Search (video)
- Binary Search (video)
- detail
- Implement:
- binary search (on sorted array of integers)
- binary search using recursion
-
- Bits cheat sheet - you should know many of the powers of 2 from (2^1 to 2^16 and 2^32)
- Get a really good understanding of manipulating bits with: &, |, ^, ~, >>, <<
- 2s and 1s complement
- count set bits
- swap values:
- absolute value:
-
- Series: Core Trees (video)
- Series: Trees (video)
- basic tree construction
- traversal
- manipulation algorithms
- BFS(breadth-first search) and DFS(depth-first search) (video)
- BFS notes:
- level order (BFS, using queue)
- time complexity: O(n)
- space complexity: best: O(1), worst: O(n/2)=O(n)
- DFS notes:
- time complexity: O(n)
- space complexity: best: O(log n) - avg. height of tree worst: O(n)
- inorder (DFS: left, self, right)
- postorder (DFS: left, right, self)
- preorder (DFS: self, left, right)
- BFS notes:
-
- Binary Search Tree Review (video)
- Series (video)
- starts with symbol table and goes through BST applications
- Introduction (video)
- MIT (video)
- C/C++:
- Binary search tree - Implementation in C/C++ (video)
- BST implementation - memory allocation in stack and heap (video)
- Find min and max element in a binary search tree (video)
- Find height of a binary tree (video)
- Binary tree traversal - breadth-first and depth-first strategies (video)
- Binary tree: Level Order Traversal (video)
- Binary tree traversal: Preorder, Inorder, Postorder (video)
- Check if a binary tree is binary search tree or not (video)
- Delete a node from Binary Search Tree (video)
- Inorder Successor in a binary search tree (video)
- Implement (complete other methods later if time permits):
- insert // insert value into tree
- get_node_count // get count of values stored
- print_values // prints the values in the tree, from min to max
- delete_tree
- is_in_tree // returns true if given value exists in the tree
- get_height // returns the height in nodes (single node's height is 1)
- get_min // returns the minimum value stored in the tree
- get_max // returns the maximum value stored in the tree
- is_binary_search_tree
- delete_value
- get_successor // returns next-highest value in tree after given value, -1 if none
-
- visualized as a tree, but is usually linear in storage (array, linked list)
- Heap
- Introduction (video)
- Naive Implementations (video)
- Binary Trees (video)
- Tree Height Remark (video)
- Basic Operations (video)
- Complete Binary Trees (video)
- Pseudocode (video)
- Heap Sort - jumps to start (video)
- Heap Sort (video)
- Building a heap (video)
- MIT: Heaps and Heap Sort (video)
- CS 61B Lecture 24: Priority Queues (video)
- Linear Time BuildHeap (max-heap)
- Implement a max-heap:
- insert
- sift_up - needed for insert
- get_max - returns the max item, without removing it
- get_size() - return number of elements stored
- is_empty() - returns true if heap contains no elements
- extract_max - returns the max item, removing it
- sift_down - needed for extract_max
- remove(i) - removes item at index x
- heapify - create a heap from an array of elements, needed for heap_sort
- heap_sort() - take an unsorted array and turn it into a sorted array in-place using a max heap
- note: using a min heap instead would save operations, but double the space needed (cannot do in-place).
-
Notes:
- Implement sorts & know best case/worst case, average complexity of each:
- no bubble sort - it's terrible - O(n^2), except when n <= 16
- stability in sorting algorithms ("Is Quicksort stable?")
- Which algorithms can be used on linked lists? Which on arrays? Which on both?
- I wouldn't recommend sorting a linked list, but merge sort is doable.
- Merge Sort For Linked List
- Implement sorts & know best case/worst case, average complexity of each:
-
For heapsort, see Heap data structure above. Heap sort is great, but not stable.
-
UC Berkeley:
-
Merge sort code:
-
Quick sort code:
-
Implement:
- Mergesort: O(n log n) average and worst case
- Quicksort O(n log n) average case
- Selection sort and insertion sort are both O(n^2) average and worst case
- heapsort, see Heap data structure above.
-
Not required, but I recommended them:
As a summary, here is a visual representation of 15 sorting algorithms. If you need more detail on this subject, see "Sorting" section in Additional Detail on Some Subjects
Graphs can be used to represent many problems in computer science, so this section is long, like trees and sorting were.
-
Notes:
- There are 4 basic ways to represent a graph in memory:
- objects and pointers
- adjacency matrix
- adjacency list
- adjacency map
- Familiarize yourself with each representation and its pros & cons
- BFS and DFS - know their computational complexity, their tradeoffs, and how to implement them in real code
- When asked a question, look for a graph-based solution first, then move on if none.
- There are 4 basic ways to represent a graph in memory:
-
MIT(videos):
-
Skiena Lectures - great intro:
- CSE373 2012 - Lecture 11 - Graph Data Structures (video)
- CSE373 2012 - Lecture 12 - Breadth-First Search (video)
- CSE373 2012 - Lecture 13 - Graph Algorithms (video)
- CSE373 2012 - Lecture 14 - Graph Algorithms (con't) (video)
- CSE373 2012 - Lecture 15 - Graph Algorithms (con't 2) (video)
- CSE373 2012 - Lecture 16 - Graph Algorithms (con't 3) (video)
-
Graphs (review and more):
- 6.006 Single-Source Shortest Paths Problem (video)
- 6.006 Dijkstra (video)
- 6.006 Bellman-Ford (video)
- 6.006 Speeding Up Dijkstra (video)
- Aduni: Graph Algorithms I - Topological Sorting, Minimum Spanning Trees, Prim's Algorithm - Lecture 6 (video)
- Aduni: Graph Algorithms II - DFS, BFS, Kruskal's Algorithm, Union Find Data Structure - Lecture 7 (video)
- Aduni: Graph Algorithms III: Shortest Path - Lecture 8 (video)
- Aduni: Graph Alg. IV: Intro to geometric algorithms - Lecture 9 (video)
-
CS 61B 2014 (starting at 58:09) (video) - CS 61B 2014: Weighted graphs (video)
- Greedy Algorithms: Minimum Spanning Tree (video)
- Strongly Connected Components Kosaraju's Algorithm Graph Algorithm (video)
-
Full Coursera Course:
-
I'll implement:
- DFS with adjacency list (recursive)
- DFS with adjacency list (iterative with stack)
- DFS with adjacency matrix (recursive)
- DFS with adjacency matrix (iterative with stack)
- BFS with adjacency list
- BFS with adjacency matrix
- single-source shortest path (Dijkstra)
- minimum spanning tree
- DFS-based algorithms (see Aduni videos above):
- check for cycle (needed for topological sort, since we'll check for cycle before starting)
- topological sort
- count connected components in a graph
- list strongly connected components
- check for bipartite graph
-
- You probably won't see any dynamic programming problems in your interview, but it's worth being able to recognize a problem as being a candidate for dynamic programming.
- This subject can be pretty difficult, as each DP soluble problem must be defined as a recursion relation, and coming up with it can be tricky.
- I suggest looking at many examples of DP problems until you have a solid understanding of the pattern involved.
- Videos:
- the Skiena videos can be hard to follow since he sometimes uses the whiteboard, which is too small to see
- Skiena: CSE373 2012 - Lecture 19 - Introduction to Dynamic Programming (video)
- Skiena: CSE373 2012 - Lecture 20 - Edit Distance (video)
- Skiena: CSE373 2012 - Lecture 21 - Dynamic Programming Examples (video)
- Skiena: CSE373 2012 - Lecture 22 - Applications of Dynamic Programming (video)
- Simonson: Dynamic Programming 0 (starts at 59:18) (video)
- Simonson: Dynamic Programming I - Lecture 11 (video)
- Simonson: Dynamic programming II - Lecture 12 (video)
- List of individual DP problems (each is short): Dynamic Programming (video)
- Yale Lecture notes:
- Coursera:
-
- Optional: UML 2.0 Series (video)
- SOLID OOP Principles: SOLID Principles (video)
-
- Quick UML review (video)
- Learn these patterns:
- strategy
- singleton
- adapter
- prototype
- decorator
- visitor
- factory, abstract factory
- facade
- observer
- proxy
- delegate
- command
- state
- memento
- iterator
- composite
- flyweight
- Chapter 6 (Part 1) - Patterns (video)
- Chapter 6 (Part 2) - Abstraction-Occurrence, General Hierarchy, Player-Role, Singleton, Observer, Delegation (video)
- Chapter 6 (Part 3) - Adapter, Facade, Immutable, Read-Only Interface, Proxy (video)
- Series of videos (27 videos)
- Head First Design Patterns
- I know the canonical book is "Design Patterns: Elements of Reusable Object-Oriented Software", but Head First is great for beginners to OO.
- Handy reference: 101 Design Patterns & Tips for Developers
- Design patterns for humans
-
- Math Skills: How to find Factorial, Permutation and Combination (Choose) (video)
- Make School: Probability (video)
- Make School: More Probability and Markov Chains (video)
- Khan Academy:
- Course layout:
- Just the videos - 41 (each are simple and each are short):
-
- Know about the most famous classes of NP-complete problems, such as traveling salesman and the knapsack problem, and be able to recognize them when an interviewer asks you them in disguise.
- Know what NP-complete means.
- Computational Complexity (video)
- Simonson:
- Skiena:
- Complexity: P, NP, NP-completeness, Reductions (video)
- Complexity: Approximation Algorithms (video)
- Complexity: Fixed-Parameter Algorithms (video)
- Peter Norvig discusses near-optimal solutions to traveling salesman problem:
- Pages 1048 - 1140 in CLRS if you have it.
-
- Computer Science 162 - Operating Systems (25 videos):
- for processes and threads see videos 1-11
- Operating Systems and System Programming (video)
- What Is The Difference Between A Process And A Thread?
- Covers:
- Processes, Threads, Concurrency issues
- difference between processes and threads
- processes
- threads
- locks
- mutexes
- semaphores
- monitors
- how they work
- deadlock
- livelock
- CPU activity, interrupts, context switching
- Modern concurrency constructs with multicore processors
- Paging, segmentation and virtual memory (video)
- Interrupts (video)
- Process resource needs (memory: code, static storage, stack, heap, and also file descriptors, i/o)
- Thread resource needs (shares above (minus stack) with other threads in the same process but each has its own pc, stack counter, registers, and stack)
- Forking is really copy on write (read-only) until the new process writes to memory, then it does a full copy.
- Context switching
- How context switching is initiated by the operating system and underlying hardware
- Processes, Threads, Concurrency issues
- threads in C++ (series - 10 videos)
- concurrency in Python (videos):
- Computer Science 162 - Operating Systems (25 videos):
-
- To cover:
- how unit testing works
- what are mock objects
- what is integration testing
- what is dependency injection
- Agile Software Testing with James Bach (video)
- Open Lecture by James Bach on Software Testing (video)
- Steve Freeman - Test-Driven Development (that’s not what we meant) (video)
- Dependency injection:
- How to write tests
- To cover:
-
- in an OS, how it works
- can be gleaned from Operating System videos
-
- Sedgewick - Suffix Arrays (video)
- Sedgewick - Substring Search (videos)
- Search pattern in text (video)
If you need more detail on this subject, see "String Matching" section in Additional Detail on Some Subjects
-
- Note there are different kinds of tries. Some have prefixes, some don't, and some use string instead of bits to track the path.
- I read through code, but will not implement.
- Sedgewick - Tries (3 videos)
- Notes on Data Structures and Programming Techniques
- Short course videos:
- The Trie: A Neglected Data Structure
- TopCoder - Using Tries
- Stanford Lecture (real world use case) (video)
- MIT, Advanced Data Structures, Strings (can get pretty obscure about halfway through) (video)
-
- Big And Little Endian
- Big Endian Vs Little Endian (video)
- Big And Little Endian Inside/Out (video)
- Very technical talk for kernel devs. Don't worry if most is over your head.
- The first half is enough.
-
- if you have networking experience or want to be a reliability engineer or operations engineer, expect questions
- otherwise, this is just good to know
- Khan Academy
- UDP and TCP: Comparison of Transport Protocols (video)
- TCP/IP and the OSI Model Explained! (video)
- Packet Transmission across the Internet. Networking & TCP/IP tutorial. (video)
- HTTP (video)
- SSL and HTTPS (video)
- SSL/TLS (video)
- HTTP 2.0 (video)
- Video Series (21 videos) (video)
- Subnetting Demystified - Part 5 CIDR Notation (video)
- Sockets:
This section will have shorter videos that you can watch pretty quickly to review most of the important concepts.
It's nice if you want a refresher often.
- Series of 2-3 minutes short subject videos (23 videos)
- Series of 2-5 minutes short subject videos - Michael Sambol (18 videos):
- Sedgewick Videos - Algorithms I
- Sedgewick Videos - Algorithms II