Dave T dtroupe18

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

	# A 3x3 magic square is a 3x3 grid of the numbers 1-9 such that each row
	# column and major diagonal adds up to 15

	# Write a function that, given a grid containing the numbers 1-9,
	# determines whether it's a magic square.
	# Use whatever format you want for the grid, such as a 2-dimensional array,
	# or a 1-dimensional array of length 9, or a function that takes 9 arguments.
	# You do not need to parse the grid from the program's input,
	# but you can if you want to. You don't need to check that each of the 9 numbers
	# appears in the grid: assume this to be true



	class State(): # class that represents the current state of the problem as we work on it

	def __init__(self, cannibalLeft, missionaryLeft, boat, cannibalRight, missionaryRight):
	self.cannibalLeft = cannibalLeft
	self.cannibalRight = cannibalRight
	self.missionaryLeft = missionaryLeft
	self.missionaryRight = missionaryRight
	self.boat = boat

	# p = an array of numbers, where p[i] represents the side length of a matrix
	# example p = [5, 2, 3] 5 x 2 and 2 x 3 matrix in that order


	def MatrixChainMult(p):
	n = len(p) - 1 # number of matrices in our multiplication problem

	cost = [[0 for i in range(n)] for j in range(n)]
	# creates and n x n matrix, we could use (n-1)x(n-1) matrix

	# items is a set of tuples (itemName, weight, value)
	# limit is the max amount of weight the knapsack can hold
	# this algorithm assumes each item can only be taken once!

	def KnapSack(items, limit):
	# initialize a table with all zero values item rows and weight columns!
	table = [[0 for w in range(limit + 1)] for j in range(len(items) + 1)]


	# iterate over each row