Implement a min-heap, Data Structure & Algorithms


A heap is an efficient tree-based data structure that can be used as a priority queue. Recall that the abstract data type of a priority queue has the following operations

  • size, isEmpty, min
  • insert
  • removeMin

We can describe the priority queue ADT using the following Java Entry class and interface:

1 import java.lang.Comparable;


3 /**

4 * When items are added to the heap, you should create an Entry object

5 * to hold the key and value and store this in the appropriate node

6 */

7 public class Entryextends Comparable,V> {

8 protected K key;

9 protected V value;

10 public MyEntry(K k, V v) { key = k; value = v; }

11 public K getKey() { return key; }

12 public V getValue() { return value; }

13 public String toString() { return "(" + key + "," + value + ")"; }

14 }


16 public interface PriorityQueueextends Comparable,V> {

17 /** Returns the number of items in the priority queue. */

18 public int size();

19 /** Returns whether the priority queue is empty. */

20 public boolean isEmpty();

21 /** Returns but does not remove an entry with minimum key. */

22 public Entry min();

23 /** Inserts a key-value pair and return the entry created. */

24 public Entry insert(K key, V value);

25 /** Removes and returns an entry with minimum key. */

26 public Entry removeMin();

27 }


The main operations (insert, removeMin) can be done in O(log n) with a heap, while the other operations of the priority queue ADT (isEmpty, size, or look up the min value) are constant time. In lectures we have seen how to implement a heap using an array-based implementation.

58_Implement a min-heap.png

Figure 1: 3-way heap example

For this assignment you must implement a min-heap using a using a tree-based implementation (similar to the binary tree class we have used in tutorials). This tree should be 3-way tree, where each node needs to have (at most) three children

Note that the definition of a 3-way heap is identical to that of a binary heap, except for allowing at most three children (see Figure ). As with a binary tree, every node must have all of its children, except for the nodes at the last levels of the tree. In more detail, your task is to

1. Design a 3-way tree structure that you will use for building your heap. You can use code provided in the book. You can use any helper data structures that you need (linked lists, arrays etc.), but you must implement the tree structure yourself.

2. Implement your design for a generic 3-way heap in a class called ThreewayHeap. You will need to implement all operations (insert, removeMin, isEmpty, etc.) in the supplied interface and skeleton for the 3-way heap. In most cases the extension is straightforward from binary heaps, with certain extra cases that you need to check.

3. Include a method in your heap to print out a visual representation in DOT format (helpful for testing/debugging purposes).

4. Design test cases for your new heap structure, used as a priority queue

5. Use the provided test code on your implementation

Posted Date: 2/28/2013 3:10:39 AM | Location : United States

Related Discussions:- Implement a min-heap, Assignment Help, Ask Question on Implement a min-heap, Get Answer, Expert's Help, Implement a min-heap Discussions

Write discussion on Implement a min-heap
Your posts are moderated
Related Questions
Merging 4 sorted files having 50, 10, 25 and 15 records will take time  O (100)

Define an array. Array is made up of same data structure that exists in any language. Array is set of same data types. Array is the collection of same elements. These same elem

I need to know about data structure and algorithms. can you help me?

human resource management project work in c++

Multilist Representation of graph

Time Complexity, Big O notation The amount of time needed by an algorithm to run to its completion is referred as time complexity. The asymptotic running time of an algorithm i

Q. The reason bubble sort algorithm is inefficient is that it continues execution even after an array is sorted by performing unnecessary comparisons. Therefore, the number of comp

how I can easily implement the bubble,selection,linear,binary searth algorithms?

if two relations R and S are joined, then the non matching tuples of both R and S are ignored in