# Data Structure Online Quiz

Welcome to our Data Structures Online Quiz designed to test and reinforce your understanding of fundamental and advanced data structure concepts. Data structures are critical for efficiently organizing, managing, and storing data for various computing tasks. This quiz covers a range of topics, from basic array and linked list operations to more complex structures like trees and graphs. Whether you're a student, a budding programmer, or a seasoned developer, these questions will help solidify your knowledge and identify areas for improvement.

## 1. What is an array?

a) A data structure that allows elements to be accessed using multiple indices
b) A data structure that stores elements in a linear order, accessible by a single index
c) A linked list of objects
d) A dynamic data structure that grows automatically

a) Queue
b) Stack
c) Array

a) O(1)
b) O(n)
c) O(log n)
d) O(n log n)

a) Array
b) Queue
c) Tree
d) Hash table

## 5. How do you determine the height of a binary tree?

a) Number of leaf nodes
b) Number of nodes
c) The longest path from the root node to the deepest node
d) The number of branches on the longest path from root to the deepest node

## 6. What does the 'Big O' notation describe?

a) The best-case scenario in an algorithm
b) The average-case scenario in an algorithm
c) The worst-case scenario in an algorithm
d) The exact run-time of an algorithm

## 7. Which data structure would be most appropriate for implementing a browser's back button?

a) Queue
b) Stack
c) Priority queue
d) Set

## 8. What is a doubly linked list?

a) A list where each node points to the next and the previous node
b) A list that can only be read forward
c) A linked list where each node contains only one pointer to the next node
d) A linked list where each node has two pointers, each pointing to two different lists

## 9. What is the purpose of a balanced tree?

a) To ensure O(n) search time
b) To ensure O(log n) search time
c) To provide better memory utilization
d) To ensure that no leaf is much farther away from the root than any other leaf

## 10. What is graph traversal?

a) Visiting, checking, and/or updating each vertex in a graph
b) Deleting a graph
c) Connecting all vertices together without any cycles
d) Finding the shortest path between two vertices

## 11. In a priority queue, by what criteria are the elements ordered?

a) First In First Out
b) Last In First Out
c) By an associated priority
d) By the size of the elements

## 12. What is a binary search tree?

a) A tree where each node has at most three children
b) A tree where each node has at most two children
c) A linked list that allows binary search
d) An array structured as a heap

## 13. What operation is not efficient in a singly linked list?

b) Inserting at the tail

## 14. What is an adjacency list?

a) A method for storing graphs by listing all connected vertices
b) A list of all disconnected vertices
c) A specialized data structure for storing weights of edges
d) A queue used in graph algorithms

a) O(1)
b) O(n)
c) O(log n)
d) O(n log n)

a) Array
b) Hash table
c) Disjoint set
d) Binary tree

## 17. How is a trie different from a binary search tree?

a) A trie allows for faster search within textual data
b) A trie does not store keys
c) A trie has a variable number of children per node
d) All of the above

## 18. What is a common use of the stack data structure?

a) Implementing recursive algorithms
b) Implementing search algorithms
c) Balancing of symbols
d) Both a) and c) are correct

## 19. How does a circular queue differ from a regular queue?

a) It allows faster retrieval
b) It utilizes space more efficiently
c) It can only store integers
d) It is faster to update

## 20. What is a complete binary tree?

a) A binary tree where all leaf nodes are at the same level
b) A binary tree where every level, except possibly the last, is completely filled
c) A binary tree that is also a binary search tree
d) A binary tree with no more than two children per node