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-- This exercise covers the first 6 and the 8th chapters of "Learn You a Haskell for Great Good!"
-- Chapter 1 -
-- Chapter 2 -
-- Chapter 3 -
-- Chapter 4 -
-- Chapter 5 -
-- Chapter 6 -
-- Chapter 8 -
PJUllrich /
Last active April 28, 2024 14:19
Big-O Time Complexities for Elixir Data Structures

Big-O Time Complexities for Elixir data structures

Map [1]

Operation Time Complexity
Access O(log n)
Search O(log n)
Insertion O(n) for <= 32 elements, O(log n) for > 32 elements [2]
Deletion O(n) for <= 32 elements, O(log n) for > 32 elements
fauxneticien /
Last active June 23, 2023 06:22
Research knowledge base with Zotero, Highlights, and Obsidian

Research knowledge base with Zotero, Highlights, and Obsidian

Ever since I started working on my honours thesis in 2013, I had been tinkering with various workflows to manage references, PDFs, PDF annotations and notes all in some coherent way. The workflow I describe here is the latest one (February 2021 as of writing), and I think I've finally found something that satisfies a lot of the [admittedly very subjective] desiderata.

Knowledge provenance

Being [perhaps overly] wary of mis-citing something, I'd like to be able to quickly go back to the original source, and the exact page and PDF highlight that I'm referring to. For the last couple of years, I have been using the Highlights App (MacOS only, unfortunately; though there may be Windows/Linux equivalents). The two main features of Highlights are that:

  1. It automatically extracts PDF highlights and is able to keep them updated in a 'sidecar' file, so for a file like Ram_et_al_2020_Neural_Network.pdf, there'll be
ethanhuang13 / VirtualKeyboard.swift
Last active February 7, 2024 05:58
MacBook Air M1 Zhuyin Keyboard written with SwiftUI ~=300 LOC, < 4hrs
// VirtualKeyboard.swift
// MacBook Air M1 Zhuyin Keyboard
// Written with SwiftUI ~=300 LOC, < 4hrs
// Created by Ethan Huang on 2021/1/13.
// Twitter: @ethanhuang13
import SwiftUI
struct VirtualKeyboard: View {

WebAssembly 导学

提起 WebAssembly/Wasm 可能会想起它是一种可以在浏览器里运行 C/C++/Rust 的技术,实际上它是一个虚拟机标准,它的实现可以在 MCU(单片机)、移动设备、桌面电脑到服务器里面跑,可以嵌入到浏览器、嵌入到应用程序或者独立运行,没有具体的边界。


  1. 编译一次到处可运行(有点类似JVM虚拟机),源语言可以是 C/C++,Rust,Go,Swift ,TypeScript,C#,Kotlin 等等。
  2. 具体的功能依赖于导入的接口(Import API),否则只是一个单纯的运算器(栈式虚拟机)。目前接口主要有 Web JS 和 WASI 两种,前者用在浏览器里,后者可以作为独立应用程序(比如调用文件系统、socket 等)。
  3. 在 WASM 虚拟机里,只能调用宿主导入的方法和共享的内存,无法直接调用宿主的资源(比如 Web DOM 对象、文件系统等),所以天然具有沙盘安全特性。
  4. 性能很好,提供了接近本地程序的性能,同一段简单的 C 计算程序,以 WASM 方式运行大概慢 1 倍左右,相对一般动态语言慢几倍到上百倍来说,性能已非常突出。
coodoo /
Last active November 7, 2020 13:42


這是 Oct. 28 ~ Nov. 01, 2020 間於推特上舉辦的趣味面試挑戰,四天期間共 517 人次閱讀、42 人 fork sandbox,最後收到九份回答,如果這是正式面試,將錄取 5 人、備取 1 人、拒絕 3 人,也就是成功率約六成。


  • 面試時別急著跳進去回答問題,先拉高層次觀察問題的形狀,搞清楚 root cause 後再思考答案與解法

  • 過程中多詢問主考官真正想達到的目地、目前為何採取此手法、現在的做法是否遇到困難、有無解法上的限制(time, mem, cpu bound)

I was drawn to programming, science, technology and science fiction
ever since I was a little kid. I can't say it's because I wanted to
make the world a better place. Not really. I was simply drawn to it
because I was drawn to it. Writing programs was fun. Figuring out how
nature works was fascinating. Science fiction felt like a grand
Then I started a software company and poured every ounce of energy
into it. It failed. That hurt, but that part is ok. I made a lot of
mistakes and learned from them. This experience made me much, much
A program searching for solutions of a board puzzle
given by a friend.
The aim is to fill in a 8 by 8 square using the
given 8 pieces. Each piece has a particular shape and
can be rotated and flipped.
I am not satisfied with this program yet. The program
johnwgillis / How to setup GPG for
Last active April 22, 2024 17:13
How to setup GPG for signing commits with Git, SourceTree, and GitHub on Mac

How to setup GPG for signing commits with Git, SourceTree, and GitHub on Mac

  1. Install GPG tools
    1. Install GPG tools and setup pin entry by running:
    brew install gnupg pinentry-mac
    mkdir -m 700 -p ~/.gnupg
    echo "pinentry-program /usr/local/bin/pinentry-mac" >> ~/.gnupg/gpg-agent.conf
    killall gpg-agent
chrisdone / DBAPI.hs
Last active April 10, 2022 07:26
Defaulting fields in a record in Haskell
{-# LANGUAGE DataKinds #-}
-- | My database API.
module DBAPI where
import Data.Defaults
data ConnSpec p = ConnSpec
{ username :: !(Required p String)