louy2

#!/usr/env sh

# remove all files from the index
# while leaving them in working dir
git rm -r --cached .

# add everything back
# with gitignore
git add .

louy2

{-# LANGUAGE LambdaCase #-}

-- Solution to https://leetcode.com/problems/longest-valid-parentheses/
-- Same recursive algorithm with
-- 1. function
-- 2. foldl
-- 3. Reader
-- 4. ReaderT
-- 5. StateT
-- 6. foldr

louy2

{-# LANGUAGE InstanceSigs #-}

newtype Reader e a = Reader (e -> a)

runReader :: Reader e a -> e -> a
runReader (Reader f) = f

instance Functor (Reader e) where
    fmap :: (a -> b) -> Reader e a -> Reader e b
    fmap a2b (Reader e2a) = Reader (a2b . e2a)

louy2

import Data.List  (elemIndex)
import Data.Maybe (fromJust, isJust)

p :: [String] -> [[Maybe Int]]
p = fmap (fmap d)
    where
        d 'W' = Just 2
        d 'D' = Just 1
        d 'L' = Just 0
        d _   = Nothing

louy2

decode :: String -> [Int]
decode "U" = [ 0,  1]
decode "D" = [ 0, -1]
decode "L" = [-1,  0]
decode "R" = [ 1,  0]
decode _   = [ 0,  0]

(.+) :: Num a => [a] -> [a] -> [a]
(.+)  = zipWith (+)

louy2

let hash = k => Array.from(k).map(s => s.charCodeAt(0)).reduce((a, c) => a + c, 0) % 111 + 1

louy2

> error: unknown type name 'size_t'
Always put your own header files after system header files, otherwise they will not pick up system types.
Or include necessary system headers in the header file.

louy2

/* Dismiss all course updates in My Blackboard
 * 
 * To use this, copy the following script into the developer console while on the Updates page
 */
// iframeRef takes an iframe element and returns the document inside it
// Ref: https://stackoverflow.com/questions/1452871/how-can-i-access-iframe-elements-with-javascript
const iframeRef = fr => fr.contentWindow ? fr.contentWindow.document : fr.contentDocument;
// get the Blackboard main UI iframe document
const bb = iframeRef(document.querySelector('#mybbCanvas'));
// click every dismiss button

louy2

A preset locally administered MAC address is used as the BSSID of the AP. Changing the MAC address of the Wifi interface doesn't affect this.

The Internet Sharing in System Preferences invokes configd, which then communicates with wifid via IPC to change the mode of the Wifi interface.

Problem: Internet Sharing only works when Security is set to None in Wi-Fi Options. Version: macOS 10.12.4 Model: MacBook Air (13-inch, Mid 2011) Wi-Fi:

louy2

/*
 * Solving A Java Inheritance Puzzler from
 * https://llogiq.github.io/2015/07/14/inheritance.html
 */

class A {
	int x = 3;
	int a() { x++; return x + c(); } 
	int b() { return a(); }
	int c() { return x; }