Array

An array is a data structure that stores a collection of elements of the same data type in a contiguous block of memory. It allows you to access its elements using an index, which starts at 0 and goes up to the array’s size minus 1.

Implementation in different languages:

Array declaration and initialization syntax varies depending on the programming language.

• Python
• C++
• C
• Java

Python implements arrays using lists, which can store elements of various data types similar to arrays.

arr = [1, 2, 3, 4, 5] # declare a list of integers
arr[0] = 1 # set the first element to 1
arr[1] = 2 # set the second element to 2

In Java Arrays are declared using square brackets, and their elements are accessed using the array index:

int[] arr = new int[5]; // declare an integer array of size 5
arr[0] = 1; // set the first element to 1
arr[1] = 2; // set the second element to 2

C and C++, you declare arrays using square brackets and access their elements using the array index.

int arr[5]; // declare an integer array of size 5
arr[0] = 1; // set the first element to 1
arr[1] = 2; // set the second element to 2

Basic operations:

You can use arrays for a variety of basic operations, including:

1. To access array elements, you can use the array index. For instance, if you have an array named “arr”, you can access its third element by using the syntax arr[2] (assuming that the index starts at 0).
2. You can change array elements by using the array index. For example, if you want to assign the value 10 to the third element of an array named “arr”, you can use the syntax arr[2] = 10.
3. Adding elements: You can add elements to an array using methods such as append() (Python), push back() (C++), or ArrayList.add() (Java).
4. Array elements can be removed using methods such as remove() (Python), erase() (C++), or ArrayList, depending on the programming language ArrayList. remove() (Java).
5. Sorting array elements: Depending on the programming language, you can sort array elements with methods like sort() (Python), sort() (C++), or Arrays.sort() (Java)

Array’s standard problem:

• Find the highest or lowest element in an array.
• Add up all the elements in an array.
• Reverse the order of array elements.
• Find the first non-repeating element in an array.
• Find the kth largest element in an array.
• Combine two sorted arrays to create a single sorted array.
• Find the longest increasing subarray in an array.
• Rotate an array’s elements by a specified number of positions.
• Find all pairs of array elements that add up to a given sum.
• Sort an array of absolute values in non-descending order.