is a special format for storing and organizing data.

2 Classification of Data Structures

Elements that are accessed in a sequential order but may be stored unsystematically.

Elements are stored and accessed in non-sequential order.

What is ADT

Two parts of ADT

stores elements where each is a separate object

ordered list in which insertion/deletion are done at one (1) end

ordered list in which insertion/deletion are done at separate ends.

hierarchical nature of a structure in graphical form

collection of elements that do not have to be in order

 a set of vertices and set of links which connects that pair of vertices

used for retrieving either minimum or maximum element

a partially sorted binary tree

a set of ordered pairs with elements known as key value

4 main operations that could be define for each ADT

is a step-by-step set of instructions to be executed in sequence for solving a problem.

An algorithm must terminate after a specified number of steps.

Each instruction has to be clear and unambiguous.

An algorithm should have zero or more well-defined data given before the algorithm begins.

An algorithm must have one (1) or more results, with specified relation to the input.

The result of each step depends on the input and/or the result of the previous step.

repeating an action multiple times

when a function calls itself once or multiple times to solve a problem

breaking a problem into smaller subproblems

always chooses the optimal approach in solving a problem

similar to divide and conquer except that the results of the subproblems are reused for overlapping subproblems