The Wayback Machine - https://web.archive.org/web/20241109032038/https://www.geeksforgeeks.org/queue-data-structure/

Queue Data Structure

Last Updated : 03 Nov, 2024

A Queue Data Structure is a fundamental concept in computer science used for storing and managing data in a specific order. It follows the principle of "First in, First out" (FIFO), where the first element added to the queue is the first one to be removed. Queues are commonly used in various algorithms and applications for their simplicity and efficiency in managing data flow.

Queue Data Structure

Basics of Queue Data Structure

Implementation of Queues

Implementations in various Programming Languages

Implementing Other Data Structures Using Queue

Easy Problems on Queue Data Structure

Medium Problems on Queue Data Structure

Hard Problems on Queue Data Structure

Quick Links:

Recommended:

H

harendrakumar123

News

Improve

Introduction to Queue Data Structure

Similar Reads

Should we declare as Queue or Priority Queue while using Priority Queue in Java?

Queue: Queue is an Interface that extends the collection Interface in Java and this interface belongs to java.util package. A queue is a type of data structure that follows the FIFO (first-in-first-out ) order. The queue contains ordered elements where insertion and deletion of elements are done at different ends. Priority Queue and Linked List are

Static Data Structure vs Dynamic Data Structure

Data structure is a way of storing and organizing data efficiently such that the required operations on them can be performed be efficient with respect to time as well as memory. Simply, Data Structure are used to reduce complexity (mostly the time complexity) of the code. Data structures can be two types : 1. Static Data Structure 2. Dynamic Data

Applications of Queue Data Structure

Introduction : A queue is a linear data structure that follows the "first-in, first-out" (FIFO) principle. It is a collection of elements that supports two primary operations - enqueue and dequeue. In the enqueue operation, an element is added to the back of the queue, while in the dequeue operation, an element is removed from the front of the queu

Basic Operations for Queue in Data Structure

Basic Operations on Queue: Some of the basic operations for Queue in Data Structure are: enqueue() - Insertion of elements to the queue.dequeue() - Removal of elements from the queue.peek() or front()- Acquires the data element available at the front node of the queue without deleting it.rear() - This operation returns the element at the rear end w

Top 50 Problems on Queue Data Structure asked in SDE Interviews

A Queue is defined as a linear data structure that is open at both ends and the operations are performed in First In First Out (FIFO) order. We define a queue to be a list in which all additions to the list are made at one end, and all deletions from the list are made at the other end. The element which is first pushed into the order, the operation

What is Queue Data Structure?

What is Queue Data Structure?A Queue is defined as a linear data structure that is open at both ends and the operations are performed in First In First Out (FIFO) order. We define a queue to be a list in which all additions to the list are made at one end, and all deletions from the list are made at the other end. The element which is first pushed

Stack and Queue in Python using queue Module

A simple python List can act as queue and stack as well. Queue mechanism is used widely and for many purposes in daily life. A queue follows FIFO rule(First In First Out) and is used in programming for sorting and for many more things. Python provides Class queue as a module which has to be generally created in languages such as C/C++ and Java. 1.

Check if a queue can be sorted into another queue using a stack

Given a Queue consisting of first n natural numbers (in random order). The task is to check whether the given Queue elements can be arranged in increasing order in another Queue using a stack. The operation allowed are: Push and pop elements from the stack Pop (Or Dequeue) from the given Queue. Push (Or Enqueue) in the another Queue. Examples : Inp

Reversing a Queue using another Queue

Given a queue. The task is to reverse the queue using another empty queue. Examples: Input: queue[] = {1, 2, 3, 4, 5} Output: 5 4 3 2 1 Input: queue[] = {10, 20, 30, 40} Output: 40 30 20 10 Approach: Given a queue and an empty queue.The last element of the queue should be the first element of the new queue.To get the last element there is a need to

Advantages of circular queue over linear queue

Linear Queue: A Linear Queue is generally referred to as Queue. It is a linear data structure that follows the FIFO (First In First Out) order. A real-life example of a queue is any queue of customers waiting to buy a product from a shop where the customer that came first is served first. In Queue all deletions (dequeue) are made at the front and a

Difference between Queue and Deque (Queue vs. Deque)

Queue: The queue is an abstract data type or linear data structure from which elements can be inserted at the rear(back) of the queue and elements can be deleted from the front(head) of the queue. The operations allowed in the queue are:insert an element at the reardelete element from the frontget the last elementget the first elementcheck the size

Why can't a Priority Queue wrap around like an ordinary Queue?

Priority Queue: A priority queue is a special type of queue in which each element is assigned a priority value. And elements are served based on their priority. This means that elements with higher priority are served first. However, if elements with the same priority occur, they will be served in the order in which they were queued. A priority que

Can we use Simple Queue instead of Priority queue to implement Dijkstra's Algorithm?

What is Dijkstra's Algorithm? Dijkstra's Algorithm is used for finding the shortest path between any two vertices of a graph. It uses a priority queue for finding the shortest path. For more detail, about Dijkstra's Algorithm, you can refer to this article. Why Dijkstra's Algorithm uses a Priority Queue? We use min heap in Dijkstra's Algorithm beca

Turn a Queue into a Priority Queue

What is Queue?Queue is an abstract data type that is open at both ends. One end is always used to insert data (enqueue) which is basically the rear/back/tail end and the other which is the front end is used to remove data (dequeue). Queue follows First-In-First-Out (FIFO) methodology, i.e., "the data item stored first will be accessed first". Decla

Why does Queue have front but Priority-queue has top in stl?

Why does the queue have front but the priority queue has top in stl? The main difference between a queue and a priority queue is that a queue follows the FIFO (First-In-First-Out) principle, while a priority queue follows a specific priority order. In other words, the elements in a queue are processed in the order they were added, whereas the eleme

What is Circular Queue | Circular Queue meaning

A circular queue is an extended version of regular queue in which the last element of the queue is connected to the first element of the queue forming a cycle. Properties of Circular Queue: Along with the properties of a regular queue the circular queue has som other unique properties as mentioned below: Front and rear pointers: Two pointers, one a

Difference Between Linear Queue and Circular Queue

Queues are fundamental data structures in computer science that follow the First-In-First-Out (FIFO) principle. Among the various types of queues, linear queues and circular queues are commonly used. While they share some similarities, they differ significantly in structure and operational efficiency. This article explores the concepts, advantages,

Difference between Circular Queue and Priority Queue

Queues are fundamental data structures that are used to store and manage a collection of elements. While both circular queues and priority queues are types of queues, they have distinct characteristics and applications. This article will explore the key differences between circular queues and priority queues. Circular Queue:A Circular Queue is an e

What is Priority Queue | Introduction to Priority Queue

A priority queue is a type of queue that arranges elements based on their priority values. Elements with higher priority values are typically retrieved or removed before elements with lower priority values. Each element has a priority value associated with it. When we add an item, it is inserted in a position based on its priority value. There are

STL Priority Queue for Structure or Class

STL priority_queue is the implementation of Heap Data-structure. By default, it's a max heap and we can easily use it for primitive datatypes. There are some important applications of it which can be found here Prerequisite: Prioirty_queue Basics In this article, we will see how can we use priority_queue for custom datatypes like class or structure

Is array a Data Type or Data Structure?

What is Data Type? In computer programming, a data type is a classification of data that determines the type of values that can be stored, manipulated, and processed. It tells the computer what kind of data a particular variable or constant can hold, and what operations can be performed on that data. Common data types include integers, floating-poi

Data Structure Alignment : How data is arranged and accessed in Computer Memory?

Data structure alignment is the way data is arranged and accessed in computer memory. Data alignment and Data structure padding are two different issues but are related to each other and together known as Data Structure alignment. Data alignment: Data alignment means putting the data in memory at an address equal to some multiple of the word size.

Difference between data type and data structure

Data Type A data type is the most basic and the most common classification of data. It is this through which the compiler gets to know the form or the type of information that will be used throughout the code. So basically data type is a type of information transmitted between the programmer and the compiler where the programmer informs the compile

Data Structures | Queue | Question 1

Following is C like pseudo-code of a function that takes a Queue as an argument, and uses a stack S to do processing. C/C++ Code void fun(Queue *Q) { Stack S; // Say it creates an empty stack S // Run while Q is not empty while (!isEmpty(Q)) { // deQueue an item from Q and push the dequeued item to S push(&S;, deQueue(Q)); } // Run while Stack S is

Data Structures | Queue | Question 2

Which one of the following is an application of Queue Data Structure? (A) When a resource is shared among multiple consumers. (B) When data is transferred asynchronously (data not necessarily received at same rate as sent) between two processes (C) Load Balancing (D) All of the above Answer: (D) Explanation: (A) When a resource is shared among mult

Data Structures | Queue | Question 3

How many stacks are needed to implement a queue. Consider the situation where no other data structure like arrays, linked list is available to you. (A) 1 (B) 2 (C) 3 (D) 4 Answer: (B) Explanation: A queue can be implemented using two stacks. Refer this for more reference:https://www.geeksforgeeks.org/queue-using-stacks/ Hence Option(B) is the corre

Data Structures | Queue | Question 5

A priority queue can efficiently implemented using which of the following data structures? Assume that the number of insert and peek (operation to see the current highest priority item) and extraction (remove the highest priority item) operations are almost same. (A) Array (B) Linked List (C) Heap Data Structures like Binary Heap, Fibonacci Heap (D

Data Structures | Queue | Question 6

Which of the following is true about linked list implementation of queue? (A) In push operation, if new nodes are inserted at the beginning of linked list, then in pop operation, nodes must be removed from end. (B) In push operation, if new nodes are inserted at the end, then in pop operation, nodes must be removed from the beginning. (C) Both of t

Data Structures | Queue | Question 11

Suppose a circular queue of capacity (n – 1) elements is implemented with an array of n elements. Assume that the insertion and deletion operation are carried out using REAR and FRONT as array index variables, respectively. Initially, REAR = FRONT = 0. The conditions to detect queue full and queue empty are (A) Full: (REAR+1) mod n == FRONT, empty:

Data Structures | Queue | Question 8

A Priority-Queue is implemented as a Max-Heap. Initially, it has 5 elements. The level-order traversal of the heap is given below: 10, 8, 5, 3, 2 Two new elements ”1‘ and ”7‘ are inserted in the heap in that order. The level-order traversal of the heap after the insertion of the elements is: (A) 10, 8, 7, 5, 3, 2, 1 (B) 10, 8, 7, 2, 3, 1, 5 (C) 10,

Article Tags :

Queue
DSA

Practice Tags :

Queue