堆排序

堆排序可以看成是另一种希尔排序，但它的增量是以2^n，即从当前节点经过父节点再到根节点组成一个子集，再对子集内元素进行插入排序。堆排序是一种不稳定排序。平均时间复杂度是0(nlogn)。

public class HeapSort {public HeapSort(){}private static void CreatMinHeap(int[] array,int start,int end){if(start>end || start<0 || end>array.length){System.out.println("Input Error!");System.exit(-1);}int temp = array[start];int i = start;int j = i*2+1;while(j<end){if(j+1<end && array[j+1]<array[j]) j++;if(array[j]<temp){System.out.println("i:"+i+"\t"+"array[i]:"+array[i]);array[i] = array[j];i = j;j = 2*i+1;}else break;}array[i] = temp;}private static void CreatMaxHeap(int[] array, int start, int end){if(start>end || start<0 || end>array.length){System.out.println("Input Error!");System.exit(-1);}int temp = array[start];int i = start;int j = i*2+1;while(j<end){if(j+1<end && array[j+1]>array[j]) j++;if(array[j]>temp){System.out.println("i:"+i+"\t"+"array[i]:"+array[i]);array[i] = array[j];i = j;j = 2*i+1;}else break;}array[i] = temp;}public static int[] sort(int[] array,String rule){if(!rule.equalsIgnoreCase("increase") && !rule.equalsIgnoreCase("decrease")){System.out.println("Please input the right define of rule: [increase] or [decrease]!");System.exit(-1);}int[] arraySorted = array.clone();//建立堆for(int i=arraySorted.length/2-1;i>=0;i--){if(rule.equalsIgnoreCase("increase"))CreatMaxHeap(arraySorted,i,arraySorted.length);else if(rule.equalsIgnoreCase("decrease"))CreatMinHeap(arraySorted,i,arraySorted.length);}//堆排序for(int i=arraySorted.length-1;i>=0;i--){int temp = arraySorted[0];arraySorted[0] = arraySorted[i];arraySorted[i] = temp;if(rule.equalsIgnoreCase("increase"))CreatMaxHeap(arraySorted,0,i);else if(rule.equalsIgnoreCase("decrease"))CreatMinHeap(arraySorted,0,i);}return arraySorted;}private static void print(int[] array){for(int i=0;i<array.length;i++){System.out.print(array[i]+" ");}System.out.println();}public static void main(String[] args){int[] array = new int[]{1,10,3,5,2,4,9,11};int[] arraySort = sort(array,"increase");System.out.println("Before sort:");print(array);System.out.println("After sort:");print(arraySort);}}