Chapter 01 -- Why Data Structures Matter

Data

Information such as numbers, strings, or values used by a program

Data structure

A way of organizing data so it can be used efficiently

Why data structures matter

The way data is organized can affect how fast code runs

Code efficiency

How fast code runs based on the number of computational steps it takes

Measuring speed

Counting how many computational steps an operation takes instead of using seconds

Array

A foundational data structure that stores values in an ordered list

Array size

The number of elements in an array

Index

The position number of a value inside an array, usually starting at 0

Read

Looking up a value at a specific index

Search

Looking for a specific value and finding where it is located

Insert

Adding a new value to a data structure

Delete

Removing a value from a data structure

Reading from an array

Fast because the computer can jump directly to a known index

Searching an array

Slower because the computer may need to check each value one by one

Linear search

Searching by checking each value one at a time

Worst-case array search

Searching may take N steps if the array has N elements

Insertion at the end of an array

Fast because no existing values need to shift

Insertion in the middle of an array

Slower because values must shift right to make room

Insertion at the beginning of an array

Slowest array insertion because all existing values must shift right

Deletion from an array

Removing a value and shifting remaining values left if needed

Deletion at the beginning of an array

Slow because the remaining values must shift left

Deletion at the end of an array

Fast because no shifting is needed

Set

A data structure similar to an array, but duplicates are not allowed

Array-based set

A set built like an array, but it checks for duplicates before insertion

Why set insertion is slower

The set must search first to make sure the value is not already present

Array vs set

Arrays allow duplicates; sets prevent duplicates

When to use an array

Use an array when duplicates are allowed and simple insertion matters

When to use a set

Use a set when duplicate values must be prevented

Main lesson of Chapter 01

Choosing the right data structure affects the efficiency of your co