I liked the way Grokking the coding interview organized problems into learnable patterns. However, the course is expensive and the majority of the time the problems are copy-pasted from leetcode. As the explanations on leetcode are usually just as good, the course really boils down to being a glorified curated list of leetcode problems.
So below I made a list of leetcode problems that are as close to grokking problems as possible.
This is a short post that explains how to write a high-performance matrix multiplication program on modern processors. In this tutorial I will use a single core of the Skylake-client CPU with AVX2, but the principles in this post also apply to other processors with different instruction sets (such as AVX512).
Matrix multiplication is a mathematical operation that defines the product of
L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns
Compress 1K bytes with Zippy ............. 3,000 ns = 3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns = 20 µs
SSD random read ........................ 150,000 ns = 150 µs
Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs
| ;SMBDIS.ASM - A COMPREHENSIVE SUPER MARIO BROS. DISASSEMBLY | |
| ;by doppelganger (doppelheathen@gmail.com) | |
| ;This file is provided for your own use as-is. It will require the character rom data | |
| ;and an iNES file header to get it to work. | |
| ;There are so many people I have to thank for this, that taking all the credit for | |
| ;myself would be an unforgivable act of arrogance. Without their help this would | |
| ;probably not be possible. So I thank all the peeps in the nesdev scene whose insight into | |
| ;the 6502 and the NES helped me learn how it works (you guys know who you are, there's no |
For a brief user-level introduction to CMake, watch C++ Weekly, Episode 78, Intro to CMake by Jason Turner. LLVM’s CMake Primer provides a good high-level introduction to the CMake syntax. Go read it now.
After that, watch Mathieu Ropert’s CppCon 2017 talk Using Modern CMake Patterns to Enforce a Good Modular Design (slides). It provides a thorough explanation of what modern CMake is and why it is so much better than “old school” CMake. The modular design ideas in this talk are based on the book [Large-Scale C++ Software Design](https://www.amazon.de/Large-Scale-Soft
Press minus + shift + s and return to chop/fold long lines!
These are instructions for setting up git to authenticate with GitHub when you have 2-factor authentication set up. This authentication should be inherited by any GUI client you are using. These are intentionally brief instructions, with links to more detail in the appropriate places.
Download and install the git command-line client (if required).
Open the git bash window and introduce yourself to git (if required):
git config --global user.name 'Firstname Lastname'
git config --global user.email 'firstname.lastname@gov.bc.ca'
The following are examples of the four types rate limiters discussed in the accompanying blog post. In the examples below I've used pseudocode-like Ruby, so if you're unfamiliar with Ruby you should be able to easily translate this approach to other languages. Complete examples in Ruby are also provided later in this gist.
In most cases you'll want all these examples to be classes, but I've used simple functions here to keep the code samples brief.
This uses a basic token bucket algorithm and relies on the fact that Redis scripts execute atomically. No other operations can run between fetching the count and writing the new count.