Java数据结构与排序算法——堆和堆排序

 

class Node_Heap{
	public int iData;

	public Node_Heap(int iData) {	//构造函数
		super();
		this.iData = iData;
	}

	public int getiData() {
		return iData;
	}

	public void setiData(int iData) {
		this.iData = iData;
	}
}

class Heap{
	private Node_Heap[] heapArray;
	public int maxSize;
	private int currentSize;
	
	public Heap(int maxSize) {	//构造函数
		super();
		this.maxSize = maxSize;
		this.currentSize = 0;
		heapArray = new Node_Heap[maxSize];
	}
	
	public boolean isEmpty(){
		return currentSize ==0;
	}
	
	public boolean insert(int key){
		if(currentSize == maxSize){
			return false;
		}
		Node_Heap newNode = new Node_Heap(key);	
		heapArray[currentSize] = newNode;	//把插入的节点放在最后的位置
		trickleUp(currentSize++);		//插入节点并把currentSize加1
		return true;
	}
	
	//用于插入，把父类节点下移，然后把插入的节点放到合适的位置
	public void trickleUp(int index){
		int parent = (index-1)/2;
		Node_Heap bottom = heapArray[index];		//暂存新插入的节点，因为需要把父节点下移
		while(index>0 &amp;&amp; heapArray[parent].getiData()<bottom.getiData()){	//如果小，就下移
			heapArray[index] = heapArray[parent];		//把父类节点下移
			index = parent;						//用于递归
			parent = (parent-1)/2;
		}
		heapArray[index] = bottom;	//把插入的节点放到合适的位置
	}
	
	public Node_Heap remove(){	//删除最大的节点
		Node_Heap root = heapArray[0];
		heapArray[0]=heapArray[--currentSize];
		trickleDown(0);
		return root;
	}
	
	//用于删除，把子类节点上移
	public void trickleDown(int index){
		int largerChild;
		Node_Heap top = heapArray[index];		//
		while(index<currentSize/2){	//如果小，就下移
			int leftChild = 2*index+1;
			int rightChild = leftChild+1;
			if(rightChild<currentSize &amp;&amp; heapArray[leftChild].getiData() < heapArray[rightChild].getiData())
				largerChild = rightChild;
			else
				largerChild = leftChild;
			if(top.getiData()>=heapArray[largerChild].getiData())
				break;
			heapArray[index] = heapArray[largerChild];
			index = largerChild;
		}
		heapArray[index] = top;	
	}
	
	public void displayHeap(){
		System.out.print("heapArray:");
		for(int i=0;i<heapArray.length;i++){
			if(heapArray[i] != null)
				System.out.print(heapArray[i].getiData()+" ");
			else
				System.out.print(" -- ");
		}
		System.out.println();
		
		int nBlanks = 32;			//定义空格
		int itemsPerRow = 1;
		int column = 0;
		int j=0;				//标记当前的数组下标，从0开始
		System.out.println("......................................................");
		while(currentSize > 0){
			if(column == 0){
				for(int i=0;i<nBlanks;i++){
					System.out.print(" ");
				}
			}
			System.out.print(heapArray[j].getiData());
			if(++j == currentSize){
				break;
			}
			if(++column==itemsPerRow){		//如果每一行计数等于这一行的上限，则换行
				nBlanks /= 2;				//空格数减半
				itemsPerRow *= 2;		//每一行的上限
				column = 0;
				System.out.println();
			}else{
				for(int i=0;i<nBlanks*2-2;i++){
					System.out.print(" ");
				}
			}
		}
		System.out.println("\n"+"......................................................");
	}
	
}

public class Heap_demo {

	public static void main(String[] args) {
		// TODO 自动生成的方法存根
		int anArrays[]={1,2,3,4,5,6,7,8,9,10};
		Heap theHeap = new Heap(31);
//		theHeap.insert(1);
//		theHeap.insert(2);
//		theHeap.insert(3);
//		theHeap.insert(4);
//		theHeap.insert(5);
//		theHeap.insert(6);
		for(int i=0;i<10;i++){
			theHeap.insert(anArrays[i]);
		}
		theHeap.displayHeap();
		//theHeap.remove();
		//theHeap.displayHeap();
		for(int i=0;i<10;i++){
			anArrays[i]=theHeap.remove().iData;
		}
		for(int i=0;i<10;i++){
			System.out.print(anArrays[i]+" ");
		}
	}

}