COLUMN
Any vertical set of data in a 2D array.

MATRIX
Another name for a two dimensional data structure.

ROW
Any horizontal set of data in a 2D array.

BACKTRACKING
Working backwards from a deadend in a recursive solution.

BIG O NOTATION
A method for measuring the efficiency of sorts and searches.

CONSTANT ORDER
Where the size of the data does not affect the number of steps in an algorithm.

CUBIC ORDER
Where the number of steps in the algorithm increases at a rate of N to the 3rd.

LINEAR ORDER
Where the number of steps in the algorithm increases at the same rate as the increase in data members.

LOG₂ N ORDER
Where doubling the amount of data results in only one extra step in the algorithm.

N LOG₂ N ORDER
An algorithm where a step must be resolved at least N times.

ORDER OF ALGORITHM
A measure of the efficiency of an algorithm.

QUICKSORT
A very efficient sort which recursively splits and slightly organizes the sublists.

ITERATOR
An object associated with a list that helps with traverses.

ListIterator
Allows traversal of a list starting from any position and allows both forward and backward movement.

KEY
Unique elements in maps that are used as points of reference to other data.

MAP
A data structure that establishes a correspondence between elements of two sets of objects.

SET
A collection with no duplicate elements.

TREEMAP
A map implemented with a balanced binary search tree.

TREESET
A set implemented with a balanced binary search tree.

DOUBLY-LINKED LIST
A linked list where the data members have links to the elements on either side of themselves.

EXTERNAL POINTER
A reference from outside of a list used to track a location.

INTERNAL POINTER
References from within a list that refer to other nodes within the list.

LINKED LIST
A data structure consisting of a series of connected nodes.

NODE
An element in a list that contains data as well as a pointer to at least one other node within the list.

NULL REFERENCE
A special empty value for a pointer.

TRAVERSE
Visiting all of the nodes in a list.

BINARY TREE
A data structure where each node has zero, one, or two subnodes.

CHILD NODE
A node in a binary tree which is visually below another node.

EDGE
The connection between two nodes.

INORDER
A traversal of a binary tree which traverses the left side, then visits the node, and then traverses the right side.

LEAF
A node with no children.

PARENT NODE
A node on a binary tree that has one or two children.

POSTORDER
A binary tree traversal that traverses the left side, the right side, and then finally visits the node.

PREORDER
A binary tree traversal that visits the node before traversing either side.

ROOT NODE
The very top node of a binary tree. It has no parent nodes.

SUBTREE
A tree created by taking one node within a tree and assuming that node is the root node of a new tree.

TREE TRAVERSAL
A system that visits every node in a tree depending on a certain order (inorder, preorder, postorder).

VISITING A NODE
Accessing the data of a particular node.

REMOVE
Retrieves the first element in a queue.

ADD
Places a new element on a queue.

POP
Removing the top element off a stack.

PUSH
Adding another element to the top of a stack.

QUEUE
A data structure using a FIFO method of storage and retrieval.

STACK
A data structure using a LIFO method of storage and retrieval.

TOP
The end of a stack where all data exchanges occur.

COLLISIONS
When multiple data members of a hash table fall into the same list.

HASHING
A method of storing data with an order of O(1) when dealing with searches and insertions.

HASH CODE
A value derived from a data element used to determine where the element should be placed.

HASH TABLE
A data structure that uses hashing to organize a list.

COMPLETE TREE
A tree with no gaps on any level except for the bottom most level.

HEAP
A complete binary tree where the value in each node does not exceed the value in any of that node's subtrees.

HEAPSORT
A sorting algorithm using a heap.

PRIORITY QUEUE
A queue where more important items are removed first, regardless of the FIFO structure.