Array Data Structure Guide

An array data structure is a fundamental concept in computer science that stores a collection of elements in a contiguous block of memory. It allows for efficient access to elements using indices and is widely used in programming for organizing and manipulating data.

Array Data Structure

What is an Array?

An array is a collection of items of the same variable type that are stored at contiguous memory locations. It’s one of the most popular and simple data structures and is often used to implement other data structures. Each item in an array is indexed starting with 0 . Each element in an array is accessed through its index.

Need of Array Data Structures

Arrays are a fundamental data structure in computer science. They are used in a wide variety of applications, including:

• Storing data for processing
• Implementing data structures such as stacks and queues
• Representing data in tables and matrices
• Creating dynamic data structures such as linked lists and trees

Types of Array

There are two main types of arrays:

• One-dimensional arrays: These arrays store a single row of elements.
• Multidimensional arrays: These arrays store multiple rows of elements.

Array Operations

Common operations performed on arrays include:

• Traversal : Visiting each element of an array in a specific order (e.g., sequential, reverse).
• Insertion : Adding a new element to an array at a specific index.
• Deletion : Removing an element from an array at a specific index.
• Searching : Finding the index of an element in an array.

Applications of Array

Arrays are used in a wide variety of applications, including:

• Storing data for processing
• Implementing data structures such as stacks and queues
• Representing data in tables and matrices
• Creating dynamic data structures such as linked lists and trees

Learn Basics of Array:

• What is Array
• Introduction to Arrays – Data Structure and Algorithm Tutorials
• Applications, Advantages and Disadvantages of Array

Array in Different Language:

• Arrays in C/C++
• Arrays in Java
• Arrays in Python
• Arrays in C#
• Arrays in Javascript

Basic Operations on Array:

• Searching in Array
• Write a program to reverse an array
• Complete Guide On Array Rotations
• Search, insert and delete in an unsorted array
• Search, insert and delete in a sorted array
• Sort an Array
• Generate all subarrays

Easy Problems on Array:

• Find the largest three elements in an array
• Find Second largest element in an array
• Move all zeroes to end of array
• Rearrange array such that even positioned are greater than odd
• Rearrange an array in maximum minimum form using Two Pointer Technique
• Segregate even and odd numbers
• Reversal algorithm for array rotation
• Print left rotation of array in O(n) time and O(1) space
• Sort an array in wave form
• Sort an array which contain 1 to n values
• Count the number of possible triangles
• Print All Distinct Elements of a given integer array
• Find the element that appears once in Array where every other element appears twice
• Leaders in an array
• Find sub-array with given sum

Medium Problems on Array:

• Rearrange an array such that arr[i] = i
• Rearrange positive and negative numbers in O(n) time and O(1) extra space
• Reorder an array according to given indexes
• Search an element in a sorted and rotated array
• Find the Rotation Count in Rotated Sorted array
• K-th Largest Sum Contiguous Subarray
• Find the smallest missing number
• Difference Array | Range update query in O(1)
• Maximum profit by buying and selling a share at most twice
• Smallest subarray with sum greater than a given value
• Inversion count in Array using Merge Sort
• Sort an array of 0s, 1s and 2s
• Merge two sorted arrays with O(1) extra space
• Majority Element
• Two Pointers Technique
• Find a peak element
• Find a triplet that sum to a given value
• Minimum increment by k operations to make all elements equal
• Equilibrium index of an array

Hard Problems on Array:

• Find k numbers with most occurrences in the given array
• MO’s Algorithm
• Square Root (Sqrt) Decomposition Algorithm
• Sparse Table
• Range sum query using Sparse Table
• Range Minimum Query (Square Root Decomposition and Sparse Table)
• Range LCM Queries
• Merge Sort Tree for Range Order Statistics
• Minimum number of jumps to reach end
• Space optimization using bit manipulations
• Sort a nearly sorted (or K sorted) array
• Find maximum value of Sum( i*arr[i]) with only rotations on given array allowed
• Median in a stream of integers (running integers)
• Construct an array from its pair-sum array
• Maximum equlibrium sum in an array
• Smallest Difference Triplet from Three arrays
• Find all triplets with zero sum
  

Quick Links :

• ‘Practice Problems’ on Arrays
• ‘Quizzes’ on Arrays
• ‘Video Tutorials’ on Arrays

Recommended:

• Learn Data Structure and Algorithms | DSA Tutorial
• Introduction to Arrays – Data Structure and Algorithm Tutorials
• Introduction to Matrix or Grid – Data Structure and Algorithms Tutorial