Java Program To Implement Meldable Heap
Chapter:
Data Structures
Last Updated:
13-07-2016 09:57:22 UTC
Program:
/* ............... START ............... */
import java.util.Scanner;
import java.util.Random;
class Node {
Node left, right, parent;
int x;
public Node(Node parent, Node left, Node right, int x) {
this.parent = parent;
this.left = left;
this.right = right;
this.x = x;
}
}
class MeldableHeap {
private Random rand;
private int n;
private Node root;
public MeldableHeap() {
root = null;
rand = new Random();
n = 0;
}
public boolean isEmpty() {
return root == null;
}
public void makeEmpty() {
root = null;
rand = new Random();
n = 0;
}
public int getSize() {
return n;
}
public void add(int x) {
Node u = new Node(null, null, null, x);
root = meld(u, root);
root.parent = null;
n++;
}
public int remove() {
int x = root.x;
root = meld(root.left, root.right);
if (root != null)
root.parent = null;
n--;
return x;
}
public Node meld(Node q1, Node q2) {
if (q1 == null)
return q2;
if (q2 == null)
return q1;
if (q2.x < q1.x)
return meld(q2, q1);
if (rand.nextBoolean()) {
q1.left = meld(q1.left, q2);
q1.left.parent = q1;
} else {
q1.right = meld(q1.right, q2);
q1.right.parent = q1;
}
return q1;
}
public void displayHeap() {
System.out.print("\nMeldable Heap : ");
if (root == null) {
System.out.print("Empty\n");
return;
}
Node prev, w = root;
while (w.left != null)
w = w.left;
while (w != null) {
System.out.print(w.x + " ");
prev = w;
w = nextNode(w);
}
System.out.println();
}
private Node nextNode(Node w) {
if (w.right != null) {
w = w.right;
while (w.left != null)
w = w.left;
} else {
while (w.parent != null && w.parent.left != w)
w = w.parent;
w = w.parent;
}
return w;
}
}
public class JavaMeldableHeapExample {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.println("Meldable Heap Test\n\n");
MeldableHeap mh = new MeldableHeap();
char ch;
do {
System.out.println("\nMeldable Heap Operations\n");
System.out.println("1. add");
System.out.println("2. remove");
System.out.println("3. size");
System.out.println("4. check empty");
System.out.println("5. clear");
int choice = scan.nextInt();
switch (choice) {
case 1:
System.out.println("Enter integer element to insert");
mh.add(scan.nextInt());
break;
case 2:
System.out.println("Removed Element : " + mh.remove());
break;
case 3:
System.out.println("Size = " + mh.getSize());
break;
case 4:
System.out.println("Empty status = " + mh.isEmpty());
break;
case 5:
mh.makeEmpty();
System.out.println("Heap Cleared\n");
break;
default:
System.out.println("Wrong Entry \n ");
break;
}
mh.displayHeap();
System.out.println("\nDo you want to continue (Type y or n) \n");
ch = scan.next().charAt(0);
} while (ch == 'Y' || ch == 'y');
}
}
/* ............... END ............... */
Output
Meldable Heap Test
Meldable Heap Operations
1. add
2. remove
3. size
4. check empty
5. clear
1
Enter integer element to insert
1
Meldable Heap : 1
Do you want to continue (Type y or n)
y
Meldable Heap Operations
1. add
2. remove
3. size
4. check empty
5. clear
1
Enter integer element to insert
2
Meldable Heap : 2 1
Do you want to continue (Type y or n)
y
Meldable Heap Operations
1. add
2. remove
3. size
4. check empty
5. clear
2
Removed Element : 1
Meldable Heap : 2
Do you want to continue (Type y or n)
n
Notes:
-
A randomized meldable heap (also Meldable Heap or Randomized Meldable Priority Queue) is a priority queue based data structure in which the underlying structure is also a heap-ordered binary tree.
Tags
Implement Meldable Heap, Java, Data Structures