堆排序

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package none012堆;//堆排序运行的时间复杂度为O(N*logN），尽管他比快速排序略慢，但他比快速排序优越的一点是//它对初始数据的分布不敏感。在关键字值按某种排列顺序的情况下，快速排序运行的时间复杂度可以降到O(N^2)级，然而堆排序对任意排列的数据，其排序的时间复杂度都是O(N*logN);//可以使用同一个数组来存放初始无序的数据，堆以及最后有序的数据，因此，堆排序不需要额外的存储空间。import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;public class HeapSortApp {/** * @param args */public static void main(String[] args) throws IOException {// TODO Auto-generated method stubint size,j;System.out.print("Enter number of items: ");size=getInt();HeapX theHeap=new HeapX(size);for(j=0;j<size;j++){int random=(int)(java.lang.Math.random()*100);NodeX newNode=new NodeX(random);theHeap.insertAt(j, newNode);theHeap.incrementSize();}System.out.print("Random: ");theHeap.displayArray();for(j=size/2-1;j>=0;j--)theHeap.trickleDown(j);System.out.print("Heap: ");theHeap.displayArray();theHeap.displayHeap();for(j=size-1;j>=0;j--){NodeX biggestNode=theHeap.remove();theHeap.insertAt(j, biggestNode);}System.out.print("Sorted: ");theHeap.displayArray();}public static String getString() throws IOException{InputStreamReader isr=new InputStreamReader(System.in);BufferedReader br=new BufferedReader(isr);String s=br.readLine();return s;}public static char getChar() throws IOException{String s=getString();return s.charAt(0);}public static int getInt() throws IOException{String s=getString();return Integer.parseInt(s);}}class NodeX{private int iData;public NodeX(int key){iData=key;}public int getKey(){return iData;} }class HeapX{private NodeX[] heapArray;private int maxSize;private int currentSize;public HeapX(int mx){maxSize=mx;currentSize=0;heapArray=new NodeX[maxSize];}public boolean isEmpty(){return currentSize==0;}  public NodeX remove(){NodeX root=heapArray[0];heapArray[0]=heapArray[--currentSize];trickleDown(0);return root;}public void trickleDown(int index){int largerChild;NodeX top=heapArray[index];while(index<currentSize/2){int leftChild=2*index+1;int rightChild=leftChild+1;if(rightChild<currentSize&&heapArray[leftChild].getKey()<heapArray[rightChild].getKey())largerChild=rightChild;else largerChild=leftChild;if(top.getKey()>=heapArray[largerChild].getKey())break;heapArray[index]=heapArray[largerChild];index=largerChild;}heapArray[index]=top;} public void displayHeap(){ int nBlanks=32;int itemsPerRow=1;int column=0;int j=0;String dots="..................................";System.out.println(dots+dots);while(currentSize>0){if(column==0)for(int k=0;k<nBlanks;k++)System.out.print(' ');System.out.print(heapArray[j].getKey());if(++j==currentSize)break;if(++column==itemsPerRow){nBlanks/=2;itemsPerRow*=2;column=0;System.out.println();}elsefor(int k=0;k<nBlanks*2-2;k++)System.out.print(' ');}System.out.println("\n"+dots+dots);}public void displayArray(){for(int j=0;j<maxSize;j++)System.out.print(heapArray[j].getKey()+" ");System.out.println("");}public void insertAt(int index,NodeX newNode){heapArray[index]=newNode;}public void incrementSize(){currentSize++;}}
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