benjamintanweihao

p(n-1, k) + p(n-1,k-1) + p(n-1,k-2)

			
#include <stdio.h>

int pascal(int n, int k) {
	int aux(int n, int k, int(*c)(int)) {
		int c1(int ret1) {
			int c2(int ret2) {
				int c3(int ret3) {			

benjamintanweihao

### Eliminate consecutive duplicates of list elements. ###

compress []     = []
compress (x:xs) = [x] ++ (compress $ dropWhile (== x) xs

### Flatten a nested list structure. ###

flatten :: NestedList a -> [a]
flatten (Elem a   )   = [a]
flatten (List (x:xs)) = flatten x ++ flatten (List xs)

benjamintanweihao

"""Translated from Haskell:
let sieve(p:xs) = p : sieve (filter (\ x -> x `mod` p /= 0) xs) in sieve [2..]
"""

from itertools import ifilter

def ints(k):
    while True:
        yield k
        k+=1

benjamintanweihao

c_cyan=`tput setaf 6`
c_sgr0=`tput setaf 14` 
 
parse_git_branch() {
  git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/(\1)/'
}

PS1="\n\[\e[30;1m\]\[\016\]\[\017\](\[\e[34;1m\]\w\[\e[30;1m\])-(\[\e[1;33m\]\@ \d\[\e[30;1m\])-(\[\e[32;1m\]\$(ls -1 | wc -l | sed 's: ::g') files, \$(ls -lah | grep -m 1 total | sed 's/total //')b\[\e[30;1m\]):\[${c_cyan}\]\e[30;1m\](\e[1;31m\]\$(parse_git_branch)\e[30;1m\]) \[\e[0m\]\n\[\e[1;33m\]#\[${c_sgr0}\] " 

benjamintanweihao

The MONGOID Cheat Sheet

( Source: the mongoid cheatsheet )

Example

  class User

include Mongoid::Document

benjamintanweihao

# First get a baseline measurement
cd /your/rails/app
time script/rails runner "puts 1"

# Install a patched ruby
curl https://gist.github.com/raw/996418/e2b346fbadeed458506fc69ca213ad96d1d08c3e/require-performance-fix-r31758.patch > /tmp/require-performance-fix.patch
rvm install ruby-head --patch /tmp/require-performance-fix.patch -n patched
# ... get a cup of tea, this took about 8 minutes on my MBP

# Get a new measurement

benjamintanweihao

function VMCheney (instructionArray, heapSlot)
{
	this.instructionArray = instructionArray;
	this.heapSlot = heapSlot;
}

VMCheney.prototype.HEAP_SIZE = 400;
VMCheney.prototype.SPACE_SIZE = 200;

VMCheney.prototype.peek = function (address, size)

benjamintanweihao

Capybara

save_and_open_page

Matchers

have_button(locator)

benjamintanweihao

defmodule Chain do
  
  # There are a couple of interesting things to note in this example.
  # Take a look at the 'counter' function:
  #   It takes in a pid, NOT 'n'. 
  #   'n' will be received in the form of a message (i.e. pid <- msg )
  # In a sense, we are 'loading/setting up' the function first.
  def counter(next_pid) do    
    receive do
      n -> 

benjamintanweihao

defmodule Echo do
  def echo(token, caller_pid) do
    IO.puts "Sending #{inspect token} to #{inspect caller_pid}"
    caller_pid <- { caller_pid, token }
  end
end

defmodule Receiver do
  def report(times) do
    Enum.map(1..times,