Self-assessment quiz

# What is a data structure? - [x] A way of organizing data to make it easier to process > ✅ A data structure organizes data to make it more manageable and easier to process. - [ ] A built-in data type > ❌ A data structure is not necessarily a built-in data type; it can be user-defined. - [x] A concrete implementation of an abstract data type > ✅ Data structures provide concrete implementations of abstract data types (ADT). - [ ] A function that manipulates data > ❌ A function manipulates data, but it is not a data structure. - [x] A way to store and retrieve data efficiently > ✅ Data structures are designed to store and retrieve data efficiently. # What is an abstract data type (ADT)? - [x] A data structure that defines operations independently of implementation > ✅ An ADT defines operations independently of how the data is represented or implemented. - [ ] A built-in type like `int` or `float` > ❌ Built-in types are not considered abstract data types. - [ ] A type of data structure specific to Python > ❌ ADTs are not language-specific and are a general concept in computer science. - [x] A data structure that abstracts away the details of implementation > ✅ ADTs abstract away the underlying implementation details, focusing on the operations that can be performed. - [ ] A data structure that is always implemented using arrays > ❌ ADTs can be implemented using a variety of structures, not just arrays. # Which of the following are examples of abstract data types? - [x] Linked list > ✅ A linked list is an abstract data type that can be implemented in various ways. - [x] Stack > ✅ A stack is an ADT with Last In First Out (LIFO) behavior. - [x] Queue > ✅ A queue is an ADT that operates on a First In First Out (FIFO) basis. - [ ] Integer > ❌ An integer is a built-in data type, not an abstract data type. - [x] Graph > ✅ A graph is an ADT used to represent relationships between objects. # What is a tree in data structures? - [x] A non-linear and hierarchical structure > ✅ Trees are hierarchical, meaning they have a parent-child relationship between elements. - [ ] A structure where each element points to exactly two other elements > ❌ This describes a binary tree, but not all trees follow this structure. - [x] A structure that has a root node and sub-nodes > ✅ In a tree, the top element is called the root node, with sub-nodes branching off from it. - [ ] A structure where all nodes are connected in a cycle > ❌ Trees are acyclic structures, meaning they do not contain cycles. - [x] A structure used to perform operations like search and traversal > ✅ Trees are commonly used for searching and traversal operations like Depth-First and Breadth-First Search. # What is a graph in data structures? - [x] A non-linear structure consisting of vertices and edges > ✅ Graphs are made up of vertices (nodes) connected by edges. - [x] A structure used to model relationships between objects > ✅ Graphs are useful for modeling relationships between interconnected objects. - [ ] A linear structure like a list > ❌ Graphs are non-linear, unlike lists. - [x] A structure that can have cycles > ✅ Unlike trees, graphs can have cycles. - [ ] A structure where every node is connected to every other node > ❌ This describes a complete graph, which is a specific type of graph, not a general characteristic.

# What is a list in Python? - [x] A data structure that stores multiple ordered values > ✅ Lists are ordered collections, meaning the position of elements matters and is based on their index. - [ ] A data structure that only allows unique values > ❌ Lists allow duplicate values, unlike sets which only allow unique values. - [x] A dynamic data structure where elements can be added or removed > ✅ Lists are dynamic and support adding or removing elements after creation. - [x] A mutable data structure > ✅ Lists are mutable, meaning their contents can be changed after they are created. - [ ] A data structure where elements are accessed using keys > ❌ Lists are indexed by position, not by keys. This behavior is specific to dictionaries. # What is a set in Python? - [x] A data structure that stores unique values > ✅ Sets only store unique elements, and duplicate entries are not allowed. - [ ] A data structure where values are indexed by position > ❌ Sets are unordered, so they do not support indexing by position. - [x] A mutable data structure > ✅ Sets in Python are mutable, allowing values to be added or removed. - [x] A data structure that does not allow duplicates > ✅ One of the key properties of sets is that they cannot contain duplicate elements. - [ ] A data structure that supports slicing like lists > ❌ Sets are unordered and do not support slicing operations like lists. # What are the properties of a tuple in Python? - [x] A tuple stores multiple values in an ordered sequence > ✅ Tuples maintain the order of elements just like lists, but they are immutable. - [ ] A tuple allows for changing its values > ❌ Tuples are immutable, meaning that their values cannot be changed after they are created. - [x] A tuple allows duplicate values > ✅ Tuples can store duplicate values, unlike sets which require elements to be unique. - [x] A tuple is a sequence data type > ✅ Tuples are sequence types, meaning they are indexed by positions starting from zero. - [ ] A tuple can be dynamically resized > ❌ Tuples are of fixed size and cannot be dynamically resized after creation. # What is a dictionary in Python? - [x] A data structure that stores key-value pairs > ✅ Dictionaries store data in key-value pairs, allowing for efficient lookups based on keys. - [x] A mutable data structure > ✅ Dictionaries are mutable, meaning you can add, modify, or remove key-value pairs. - [ ] A data structure that allows duplicate keys > ❌ Dictionaries do not allow duplicate keys; each key must be unique. - [x] A data structure that dynamically grows as key-value pairs are added > ✅ Dictionaries are dynamic and can grow as new key-value pairs are added. - [ ] A data structure where values are accessed by their position > ❌ Values in a dictionary are accessed using keys, not by their position. # Which of the following are mutable data structures in Python? - [x] List > ✅ Lists are mutable, meaning their elements can be changed. - [x] Set > ✅ Sets are mutable, allowing the addition and removal of elements. - [x] Dictionary > ✅ Dictionaries are mutable, allowing key-value pairs to be added or changed. - [ ] Tuple > ❌ Tuples are immutable, meaning they cannot be modified after creation. - [ ] String > ❌ Strings are immutable in Python and cannot be altered after they are created.

# What is a doubly-linked list? - [x] A data structure where each element is linked to its preceding and succeeding elements > ✅ In a doubly-linked list, each element contains links to both the previous and next elements in the sequence. - [ ] A data structure where elements are only linked to the succeeding element > ❌ This describes a singly-linked list, not a doubly-linked list. - [x] A structure that maintains pointers to both the head and tail > ✅ Doubly-linked lists maintain pointers to both the first (head) and last (tail) elements for efficient navigation. - [ ] A structure that stores elements in a continuous block of memory > ❌ Linked lists store elements non-contiguously, with links connecting them. - [x] A data structure used to navigate forwards and backwards through the list > ✅ The links between elements in a doubly-linked list allow for forward and backward navigation. # What operations are supported by a doubly-linked list? - [x] Insertion at the beginning > ✅ You can insert elements at the beginning of a doubly-linked list. - [x] Insertion at the end > ✅ Elements can also be inserted at the end of a doubly-linked list. - [x] Removing the head element > ✅ The head element can be removed from a doubly-linked list. - [x] Removing the tail element > ✅ You can remove the tail element from a doubly-linked list. - [ ] Direct access to an element by index > ❌ Linked lists do not support direct access by index; they require traversal to access elements. # What are the key components of a node in a doubly-linked list? - [x] Data > ✅ Each node stores data along with its links to other nodes. - [x] Link to the next node > ✅ Each node has a link to the next node in the sequence. - [x] Link to the previous node > ✅ Each node has a link to the previous node, enabling backward navigation. - [ ] Link to the tail > ❌ Each node does not link directly to the tail; only the head and tail nodes maintain such links. - [ ] Key-value pair storage > ❌ Linked list nodes do not inherently store key-value pairs like dictionaries do. # What is the advantage of a doubly-linked list over a singly-linked list? - [x] Ability to traverse the list in both directions > ✅ Doubly-linked lists allow traversal in both forward and backward directions, unlike singly-linked lists. - [ ] Simpler to implement > ❌ Doubly-linked lists are more complex to implement due to the additional links to maintain. - [x] Efficient removal of elements from both ends > ✅ With pointers to both the head and tail, removing elements from either end is efficient in doubly-linked lists. - [ ] Less memory usage > ❌ Doubly-linked lists require more memory than singly-linked lists due to the extra link for the previous node. - [x] Improved performance for certain navigation operations > ✅ The ability to move in both directions improves performance in cases where backward traversal is needed. # What happens when you insert an element at the beginning of a doubly-linked list? - [x] The new element becomes the head of the list > ✅ When an element is inserted at the beginning, it becomes the new head of the list. - [x] The previous head element's `prev` pointer is updated > ✅ The previous head element’s `prev` pointer is updated to link to the new head. - [ ] The tail element is replaced > ❌ The tail element is not replaced when inserting at the beginning. - [ ] The list is traversed to find the correct position > ❌ No traversal is needed when inserting at the beginning; the insertion is immediate. - [x] The list's `head` pointer is updated > ✅ The list's `head` pointer is updated to point to the newly inserted element.

# What is a stack in computer science? - [x] A data structure where elements are added and removed from the top > ✅ Stacks follow the Last In, First Out (LIFO) principle, where elements are added and removed from the same end, the top. - [ ] A data structure where elements are added to the front and removed from the back > ❌ This describes a queue, not a stack. Stacks only allow access to the top element. - [x] A LIFO (Last In, First Out) structure > ✅ Stacks operate based on the LIFO principle, where the most recent item added is the first one removed. - [ ] A FIFO (First In, First Out) structure > ❌ FIFO describes a queue, not a stack. In a stack, the last element added is the first to be removed. - [x] A structure used for managing function calls in programming > ✅ Stacks are commonly used to manage function calls and recursive processes in programming. # What are the main operations performed on a stack? - [x] Push > ✅ Push adds an element to the top of the stack. - [x] Pop > ✅ Pop removes the top element from the stack. - [ ] Peek > ❌ Peek is not a core operation in all stacks, though it can be used in some implementations to view the top element without removing it. - [x] Initialize > ✅ Initializing creates an empty stack, ready to hold elements. - [x] is_empty > ✅ The `is_empty` function checks if the stack contains any elements. # In which scenarios is a stack particularly useful? - [x] Managing function calls in recursive algorithms > ✅ Stacks are often used to manage function calls in recursive processes, storing return addresses and local variables. - [ ] Processing data in a FIFO order > ❌ Stacks use a LIFO order, not FIFO. FIFO is for queues. - [x] Evaluating arithmetic expressions in postfix notation > ✅ Stacks are used to evaluate arithmetic expressions in postfix notation, where operators follow operands. - [x] Backtracking algorithms > ✅ Stacks are ideal for backtracking algorithms, such as depth-first search, as they allow retracing steps when needed. - [ ] Searching for elements in a sorted list > ❌ Stacks are not typically used for searching elements in a sorted list; other data structures are more efficient for this task. # What is the function of the `push` operation in a stack? - [x] It adds an element to the top of the stack > ✅ The push operation adds an element to the top of the stack, following the LIFO principle. - [ ] It removes an element from the bottom of the stack > ❌ Push adds elements to the top, not the bottom of the stack. - [ ] It initializes the stack > ❌ Push does not initialize the stack; it only adds elements to an already initialized stack. - [x] It increases the stack's size > ✅ Each push operation increases the size of the stack by adding a new element. - [ ] It removes the last element added > ❌ Push adds elements to the stack; pop removes them. # What is the `pop` operation in a stack? - [x] It removes the top element from the stack > ✅ Pop removes and returns the topmost element in the stack. - [ ] It adds an element to the bottom of the stack > ❌ Pop does not add elements; it only removes the top element. - [x] It decreases the size of the stack by one > ✅ Each pop operation reduces the stack's size by one element. - [ ] It retrieves an element from the middle of the stack > ❌ Pop only works on the top element of the stack, not elements in the middle. - [x] It is part of the LIFO structure > ✅ Pop follows the LIFO principle, where the last element added is the first one removed.

# What is a queue in computer science? - [x] A data structure where the first element added is the first to be removed > ✅ Queues follow the First In, First Out (FIFO) principle, meaning elements are removed in the order they were added. - [ ] A data structure where the last element added is the first to be removed > ❌ This describes a stack, not a queue. Queues follow FIFO, not LIFO. - [x] A structure used in situations where order matters, such as managing a line of people > ✅ Queues are often used in real-world situations like processing a line of people, where the first to arrive is the first to be served. - [ ] A data structure where elements can be added or removed from both ends > ❌ A deque allows adding and removing from both ends, not a standard queue. - [x] A FIFO (First In, First Out) data structure > ✅ Queues follow FIFO, where the first element added is the first to be removed. # What are the main operations performed on a queue? - [x] Enqueue > ✅ Enqueue adds an element to the end of the queue. - [x] Dequeue > ✅ Dequeue removes the first element from the queue. - [ ] Peek > ❌ Peek is not a core operation in queues, though some implementations may allow peeking at the first element without removing it. - [x] Initialize > ✅ Initialization sets up an empty queue to hold elements. - [x] is_empty > ✅ The `is_empty` operation checks whether the queue contains any elements. # In which scenarios is a queue particularly useful? - [x] Managing the order of tasks in a print queue > ✅ Queues are used in print queues to manage tasks in the order they were added, ensuring that the first task submitted is the first one processed. - [ ] Processing data in a LIFO order > ❌ Queues use a FIFO order, not LIFO. LIFO is used for stacks. - [x] Handling processes in operating system scheduling > ✅ Queues are used in operating systems to manage process scheduling, ensuring that processes are handled in the order they arrive. - [ ] Evaluating arithmetic expressions in postfix notation > ❌ Stacks, not queues, are typically used for evaluating postfix expressions. - [x] Managing a line of customers at a service counter > ✅ Queues are ideal for managing lines, where the first person in line is the first to be served. # What are the characteristics of a FIFO data structure? - [x] The first element added is the first one removed > ✅ In a FIFO structure, the first element added is the first one to be removed. - [ ] The last element added is the first one removed > ❌ This describes LIFO (Last In, First Out), not FIFO. - [x] The queue is emptied in the same order as elements were added > ✅ In a queue, elements are removed in the same order they were added, following FIFO. - [ ] Elements are added and removed from both ends > ❌ Queues only allow elements to be added at the end and removed from the front. A deque allows operations at both ends. - [x] It is useful for managing tasks that must be processed in order > ✅ FIFO structures like queues are useful for processing tasks in the order they arrive. # What is the function of the `enqueue` operation in a queue? - [x] It adds an element to the end of the queue > ✅ The enqueue operation adds an element to the end of the queue, following the FIFO principle. - [ ] It removes an element from the front of the queue > ❌ Enqueue adds elements to the queue; dequeue removes them. - [ ] It initializes the queue > ❌ Enqueue does not initialize the queue; it only adds elements to an already initialized queue. - [x] It increases the queue's size > ✅ Each enqueue operation increases the size of the queue by adding a new element. - [ ] It removes the last element added > ❌ Enqueue adds elements to the queue; dequeue removes the first element added.