Emerick Bosch xpcoffee

These are part of my notes for the Coursera course: Algorithms, Pt I (Princeton).

##Stack

####Concept

one of the fundamental data types used to manage a collection of objects
works like a 'stack' of plates
plates can only be added or removed from the top of the pile

These are part of my notes for the Coursera course: Algorithms, Pt I (Princeton).

##Queue

####Concept

one of the fundamental data types used to manage a collection of objects
works like a 'queue' of people
people enter from the back of the queue and leave from the front

These are part of my notes for the Coursera course: Algorithms, Pt I (Princeton).

##Basic Mergesort

####Concept

halve array, creating 2 sub-arrays
sort each sub array
merge the sub arrays back together

These are part of my notes for the Coursera course: Algorithms, Pt I (Princeton).
Information on basic Mergesort can be found here.

##Bottom-Up Mergesort

####Concept

we know :
- normal Mergesort recurs, halving the array until we hit sub-arrays/ranges of size 1
- it is only from here that sorting starts to happen
instead of recurring down from the full array, start with ranges of size 1

These are part of my notes for the Coursera course: Algorithms, Pt I (Princeton).

##Stability (Sorts)

####Definition

ability of a sort to keep the current order of equal items while sorting.
- important if sorting by different keys (e.g. first by song name, then by artist)

####Stable sorts | Sort | Stability |

##Java Comparator Interface

####Concept

Comparables are the basic interface java offers to compare two objects
- classes that implement Comparable must provide a compareTo method
- the compareTo method determines what is known as the natural order in which objects of that class are sorted
comparators enable us to define a compare statement outside of a class
this allows us to redefine sorting order to be different than the natural order

These are part of my notes for the Coursera course: Algorithms, Pt I (Princeton).
This requires knowledge of Partitioning.

##Quicksort

####Concept

we know
partitioning places smaller items on the left and larger items on the right of a selected value

####Stack vs Heap in C-languages

Stack
A stack is memory set aside for running code. Typically, calls to functions create temporary variables.
These variables are stored on the stack.

Stacks are a LIFO (last in, first out) structure.

Heap

##Domain Name System (DNS)

This is the system that allows a pc to navigate to the right page on the internet.

###The Nature of Internet Addresses Addresses on the internet are actually IP addresses (Internet Protocol) like 74.125.228.200 - Google.

IP is well defined and standardized and it has proven to be a reliable method for locating individual devices within large networks. Browsers and computers have these standards coded in them and can use them quickly and efficiently to find and communicate with each other.

However, IP addresses are not human-friendly. Lists of four numbers are hard to remember and do not give any information about the nature of the site, for example:

	import java.util.Comparator;

	public class ThreeWayQuick{

	public static void sort(Comparable[] a)
	{
	StdRandom.shuffle(a);
	sort(a, 0, a.length - 1);
	}