11 Lecture - Implementation of Priority Queue

  1. Home
  2. Courses
  3. Data Structures
  4. 11 Lecture

11 Lecture

CS301

Midterm & Final Term Short Notes

Implementation of Priority Queue

A Priority Queue is an abstract data type that stores a collection of elements with priority values assigned to each element. The implementation of a Priority Queue involves using a data structure such as a binary heap, a Fibonacci heap, or a so


Important Mcq's
Midterm & Finalterm Prepration
Past papers included

Download PDF

  1. Which of the following data structures is commonly used to implement a Priority Queue? a) Linked List b) Queue c) Binary Heap d) Stack Solution: c) Binary Heap

  2. Which of the following operations is commonly supported by a Priority Queue? a) Enqueue b) Dequeue c) Insert d) All of the above Solution: d) All of the above

  3. What is the time complexity of inserting an element into a binary heap? a) O(1) b) O(log n) c) O(n) d) O(n log n) Solution: b) O(log n)

  4. What is the time complexity of deleting the highest-priority element from a binary heap? a) O(1) b) O(log n) c) O(n) d) O(n log n) Solution: b) O(log n)

  5. Which of the following is an advantage of using a Fibonacci Heap to implement a Priority Queue? a) Faster insert operation than a binary heap b) Lower memory usage than a binary heap c) Faster delete operation than a binary heap d) All of the above Solution: c) Faster delete operation than a binary heap

  6. Which of the following algorithms makes use of a Priority Queue? a) Dijkstra's shortest path algorithm b) Binary search algorithm c) Bubble sort algorithm d) Linear search algorithm Solution: a) Dijkstra's shortest path algorithm

  7. Which of the following data structures is commonly used to implement a Priority Queue in C++? a) std::queue b) std::vector c) std::list d) std::priority_queue Solution: d) std::priority_queue

  8. Which of the following operations is not supported by a Priority Queue? a) Changing the priority of an element b) Inserting an element c) Removing an element with the lowest priority d) Removing an element with the highest priority Solution: c) Removing an element with the lowest priority

  9. Which of the following is an application of Priority Queues? a) Sorting large datasets b) Implementing a stack c) Implementing a queue d) Task scheduling in an operating system Solution: d) Task scheduling in an operating system

  10. Which of the following is a disadvantage of using a binary heap to implement a Priority Queue? a) Slower delete operation than a Fibonacci Heap b) Higher memory usage than a Fibonacci Heap c) Slower insert operation than a Fibonacci Heap d) All of the above Solution: a) Slower delete operation than a Fibonacci Heap



Subjective Short Notes
Midterm & Finalterm Prepration
Past papers included

Download PDF

  1. What is a Priority Queue? Answer: A Priority Queue is an abstract data type that stores a collection of elements with priority values assigned to each element. Elements with higher priority values are given precedence over those with lower priority values.

  2. What is the difference between a Queue and a Priority Queue? Answer: A Queue is a data structure that follows the First-In-First-Out (FIFO) principle, while a Priority Queue follows the priority-based ordering principle. In a Queue, elements are added to the back and removed from the front, while in a Priority Queue, elements are removed based on their priority values.

  3. What are the commonly used data structures to implement a Priority Queue? Answer: The commonly used data structures to implement a Priority Queue are binary heap, Fibonacci heap, and sorted array.

  4. What is a binary heap? Answer: A binary heap is a complete binary tree where the parent node has a higher priority value than its children nodes.

  5. What are the operations that can be performed on a Priority Queue? Answer: The operations that can be performed on a Priority Queue are inserting an element, deleting the element with the highest priority, and changing the priority of an element.

  6. What is the time complexity of inserting an element into a Priority Queue? Answer: The time complexity of inserting an element into a Priority Queue depends on the implementation. For a binary heap, the time complexity is O(log n), while for a Fibonacci heap, it is O(1).

  7. What is the time complexity of deleting the element with the highest priority from a Priority Queue? Answer: The time complexity of deleting the element with the highest priority from a Priority Queue depends on the implementation. For a binary heap, the time complexity is O(log n), while for a Fibonacci heap, it is O(log n) amortized.

  8. What is the difference between a Max Heap and a Min Heap? Answer: In a Max Heap, the parent node has a higher priority value than its children nodes, while in a Min Heap, the parent node has a lower priority value than its children nodes.

  9. What is the application of Priority Queues? Answer: Priority Queues are used in various applications such as task scheduling, Dijkstra's shortest path algorithm, Huffman coding, A* search, and many more.

  10. How can a Priority Queue be implemented in C++? Answer: A Priority Queue can be implemented in C++ using the std::priority_queue class from the Standard Template Library (STL).

Priority Queue is a data structure that stores a collection of elements, each with a priority value assigned to it. It allows efficient access to the element with the highest priority value. Priority Queues are used in various applications such as task scheduling, Dijkstra's shortest path algorithm, Huffman coding, A* search, and many more. There are various ways to implement a Priority Queue such as binary heap, Fibonacci heap, sorted array, and more. The binary heap is the most commonly used implementation because of its simplicity and efficiency. It is a complete binary tree where the parent node has a higher priority value than its children nodes. The time complexity of inserting an element into a binary heap is O(log n), while deleting the element with the highest priority is also O(log n). The Fibonacci heap is another implementation that has a faster delete operation than a binary heap. It is a collection of trees that are represented as a circular doubly linked list. The time complexity of deleting the element with the highest priority is O(log n) amortized, while inserting an element is O(1) amortized. In C++, the std::priority_queue class from the Standard Template Library (STL) can be used to implement a Priority Queue. It is a container adaptor that provides a Priority Queue functionality. It is implemented using a binary heap and supports the operations of inserting an element, deleting the element with the highest priority, and accessing the element with the highest priority. It is important to note that a Priority Queue does not allow changing the priority of an element once it has been inserted. If the priority of an element needs to be changed, it has to be removed from the Priority Queue and inserted again with the updated priority. In conclusion, a Priority Queue is a useful data structure that allows efficient access to the element with the highest priority value. There are various ways to implement a Priority Queue, each with its advantages and disadvantages. The choice of implementation depends on the application and the requirements of the problem being solved.

Course Lectures