实现二项式堆的Java程序
二项式堆是一组二项式树，其中每个二项式树都遵循最小堆属性。并且最多可以有一个任意度的二叉树。下图详细解释如下：
插图：
下面描述了 2 个二项式堆，如下所示：
BINOMIAL HEAP 1
12------------10--------------------20
/ \ / | \
15 50 70 50 40
| / | |
30 80 85 65
|
100
A Binomial Heap with 13 nodes. It is a collection of 3
Binomial Trees of orders 0, 2 and 3 from left to right.
BINOMIAL HEAP 2
10--------------------20
/ \ / | \
15 50 70 50 40
| / | |
30 80 85 65
|
100
A Binomial Heap with 12 nodes. It is a collection of 2
Binomial Trees of orders 2 and 3 from left to right. 现在让我们讨论数字和二项式堆的二进制表示。具有 n 个节点的二项式堆的二项式树的数量等于 n 的二进制表示中设置位的数量。
例如，假设 n 为 13，n (00001101) 的二进制表示中有 3 个设置位，因此有 3 个二叉树。我们还可以将这些二叉树的度与设置位的位置相关联。通过这种关系，我们可以得出结论，在具有“n”个节点的二项式堆中存在 O(Logn) 棵二项式树。
二项式堆的操作如下：
- Insert(K)：在二项式堆中插入一个元素K
- Delete(k)：从堆中删除元素k
- getSize()：返回堆的大小
- makeEmpty()：通过删除所有元素使二项式堆为空
- checkEmpty()：检查二项堆是否为空
- displayHeap()：打印二项式堆
执行：
例子
Java
// Java Program to Implement Binomial Heap
// Importing required classes
import java.io.*;
// Class 1
// BinomialHeapNode
class BinomialHeapNode {
int key, degree;
BinomialHeapNode parent;
BinomialHeapNode sibling;
BinomialHeapNode child;
// Constructor of this class
public BinomialHeapNode(int k)
{
key = k;
degree = 0;
parent = null;
sibling = null;
child = null;
}
// Method 1
// To reverse
public BinomialHeapNode reverse(BinomialHeapNode sibl)
{
BinomialHeapNode ret;
if (sibling != null)
ret = sibling.reverse(this);
else
ret = this;
sibling = sibl;
return ret;
}
// Method 2
// To find minimum node
public BinomialHeapNode findMinNode()
{
// this keyword refers to current instance itself
BinomialHeapNode x = this, y = this;
int min = x.key;
while (x != null) {
if (x.key < min) {
y = x;
min = x.key;
}
x = x.sibling;
}
return y;
}
// Method 3
// To find node with key value
public BinomialHeapNode findANodeWithKey(int value)
{
BinomialHeapNode temp = this, node = null;
while (temp != null) {
if (temp.key == value) {
node = temp;
break;
}
if (temp.child == null)
temp = temp.sibling;
else {
node = temp.child.findANodeWithKey(value);
if (node == null)
temp = temp.sibling;
else
break;
}
}
return node;
}
// Method 4
// To get the size
public int getSize()
{
return (
1 + ((child == null) ? 0 : child.getSize())
+ ((sibling == null) ? 0 : sibling.getSize()));
}
}
// Class 2
// BinomialHeap
class BinomialHeap {
// Member variables of this class
private BinomialHeapNode Nodes;
private int size;
// Constructor of this class
public BinomialHeap()
{
Nodes = null;
size = 0;
}
// Checking if heap is empty
public boolean isEmpty() { return Nodes == null; }
// Method 1
// To get the size
public int getSize() { return size; }
// Method 2
// Clear heap
public void makeEmpty()
{
Nodes = null;
size = 0;
}
// Method 3
// To insert
public void insert(int value)
{
if (value > 0) {
BinomialHeapNode temp
= new BinomialHeapNode(value);
if (Nodes == null) {
Nodes = temp;
size = 1;
}
else {
unionNodes(temp);
size++;
}
}
}
// Method 4
// To unite two binomial heaps
private void merge(BinomialHeapNode binHeap)
{
BinomialHeapNode temp1 = Nodes, temp2 = binHeap;
while ((temp1 != null) && (temp2 != null)) {
if (temp1.degree == temp2.degree) {
BinomialHeapNode tmp = temp2;
temp2 = temp2.sibling;
tmp.sibling = temp1.sibling;
temp1.sibling = tmp;
temp1 = tmp.sibling;
}
else {
if (temp1.degree < temp2.degree) {
if ((temp1.sibling == null)
|| (temp1.sibling.degree
> temp2.degree)) {
BinomialHeapNode tmp = temp2;
temp2 = temp2.sibling;
tmp.sibling = temp1.sibling;
temp1.sibling = tmp;
temp1 = tmp.sibling;
}
else {
temp1 = temp1.sibling;
}
}
else {
BinomialHeapNode tmp = temp1;
temp1 = temp2;
temp2 = temp2.sibling;
temp1.sibling = tmp;
if (tmp == Nodes) {
Nodes = temp1;
}
else {
}
}
}
}
if (temp1 == null) {
temp1 = Nodes;
while (temp1.sibling != null) {
temp1 = temp1.sibling;
}
temp1.sibling = temp2;
}
else {
}
}
// Method 5
// For union of nodes
private void unionNodes(BinomialHeapNode binHeap)
{
merge(binHeap);
BinomialHeapNode prevTemp = null, temp = Nodes,
nextTemp = Nodes.sibling;
while (nextTemp != null) {
if ((temp.degree != nextTemp.degree)
|| ((nextTemp.sibling != null)
&& (nextTemp.sibling.degree
== temp.degree))) {
prevTemp = temp;
temp = nextTemp;
}
else {
if (temp.key <= nextTemp.key) {
temp.sibling = nextTemp.sibling;
nextTemp.parent = temp;
nextTemp.sibling = temp.child;
temp.child = nextTemp;
temp.degree++;
}
else {
if (prevTemp == null) {
Nodes = nextTemp;
}
else {
prevTemp.sibling = nextTemp;
}
temp.parent = nextTemp;
temp.sibling = nextTemp.child;
nextTemp.child = temp;
nextTemp.degree++;
temp = nextTemp;
}
}
nextTemp = temp.sibling;
}
}
// Method 6
// To return minimum key
public int findMinimum()
{
return Nodes.findMinNode().key;
}
// Method 7
// To delete a particular element */
public void delete(int value)
{
if ((Nodes != null)
&& (Nodes.findANodeWithKey(value) != null)) {
decreaseKeyValue(value, findMinimum() - 1);
extractMin();
}
}
// Method 8
// To decrease key with a given value */
public void decreaseKeyValue(int old_value,
int new_value)
{
BinomialHeapNode temp
= Nodes.findANodeWithKey(old_value);
if (temp == null)
return;
temp.key = new_value;
BinomialHeapNode tempParent = temp.parent;
while ((tempParent != null)
&& (temp.key < tempParent.key)) {
int z = temp.key;
temp.key = tempParent.key;
tempParent.key = z;
temp = tempParent;
tempParent = tempParent.parent;
}
}
// Method 9
// To extract the node with the minimum key
public int extractMin()
{
if (Nodes == null)
return -1;
BinomialHeapNode temp = Nodes, prevTemp = null;
BinomialHeapNode minNode = Nodes.findMinNode();
while (temp.key != minNode.key) {
prevTemp = temp;
temp = temp.sibling;
}
if (prevTemp == null) {
Nodes = temp.sibling;
}
else {
prevTemp.sibling = temp.sibling;
}
temp = temp.child;
BinomialHeapNode fakeNode = temp;
while (temp != null) {
temp.parent = null;
temp = temp.sibling;
}
if ((Nodes == null) && (fakeNode == null)) {
size = 0;
}
else {
if ((Nodes == null) && (fakeNode != null)) {
Nodes = fakeNode.reverse(null);
size = Nodes.getSize();
}
else {
if ((Nodes != null) && (fakeNode == null)) {
size = Nodes.getSize();
}
else {
unionNodes(fakeNode.reverse(null));
size = Nodes.getSize();
}
}
}
return minNode.key;
}
// Method 10
// To display heap
public void displayHeap()
{
System.out.print("\nHeap : ");
displayHeap(Nodes);
System.out.println("\n");
}
private void displayHeap(BinomialHeapNode r)
{
if (r != null) {
displayHeap(r.child);
System.out.print(r.key + " ");
displayHeap(r.sibling);
}
}
}
// Class 3
// Main class
public class GFG {
public static void main(String[] args)
{
// Make object of BinomialHeap
BinomialHeap binHeap = new BinomialHeap();
// Inserting in the binomial heap
// Custom input integer values
binHeap.insert(12);
binHeap.insert(8);
binHeap.insert(5);
binHeap.insert(15);
binHeap.insert(7);
binHeap.insert(2);
binHeap.insert(9);
// Size of binomial heap
System.out.println("Size of the binomial heap is "
+ binHeap.getSize());
// Displaying the binomial heap
binHeap.displayHeap();
// Deletion in binomial heap
binHeap.delete(15);
binHeap.delete(8);
// Size of binomial heap
System.out.println("Size of the binomial heap is "
+ binHeap.getSize());
// Displaying the binomial heap
binHeap.displayHeap();
// Making the heap empty
binHeap.makeEmpty();
// checking if heap is empty
System.out.println(binHeap.isEmpty());
}
}输出
Size of the binomial heap is 7
Heap : 9 7 2 12 8 15 5
Size of the binomial heap is 5
Heap : 7 9 5 12 2
true