堆排序（java實現）

import java.util.Arrays;

public class HeapSort {

    public static void heapSort(DataWraper[] data){
        System.out.println("開始排序");
        int arrayLength=data.length;
        //迴圈建堆
        for(int i=0;i<arrayLength-1;i++){
            //建堆
            buildMaxHeap(data,arrayLength-1-i);
            //交換堆頂和最後一個元素
            swap(data,0,arrayLength-1-i);
            System.out.println(Arrays.toString(data));
        }
    }

    private static void swap(DataWraper[] data, int i, int j) {
        // TODO Auto-generated method stub
        DataWraper tmp=data[i];
        data[i]=data[j];
        data[j]=tmp;
    }
    //對data數組從0到lastIndex建大頂堆
    private static void buildMaxHeap(DataWraper[] data, int lastIndex) {
        // TODO Auto-generated method stub
        //從lastIndex處節點（最後一個節點）的父節點開始
        for(int i=(lastIndex-1)/2;i>=0;i--){
            //k儲存正在判斷的節點
            int k=i;
            //如果當前k節點的子節點存在
            while(k*2+1<=lastIndex){
                //k節點的左子節點的索引
                int biggerIndex=2*k+1;
                //如果biggerIndex小於lastIndex，即biggerIndex+1代表的k節點的右子節點存在
                if(biggerIndex<lastIndex){
                    //若果右子節點的值較大
                    if(data[biggerIndex].compareTo(data[biggerIndex+1])<0){
                        //biggerIndex總是記錄較大子節點的索引
                        biggerIndex++;
                    }
                }
                //如果k節點的值小於其較大的子節點的值
                if(data[k].compareTo(data[biggerIndex])<0){
                    //交換他們
                    swap(data,k,biggerIndex);
                    //將biggerIndex賦予k，開始while迴圈的下一次迴圈，重新保證k節點的值大於其左右子節點的值
                    k=biggerIndex;
                }else{
                    break;
                }
            }
        }
    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        DataWraper [] data={
                new DataWraper(21, ""),
                new DataWraper(30, ""),
                new DataWraper(49, ""),
                new DataWraper(30, "*"),
                new DataWraper(16, ""),
                new DataWraper(9, ""),
               
        };
        System.out.println("排序之前：\n"+Arrays.toString(data));
        heapSort(data);
        System.out.println("排序之後：\n"+Arrays.toString(data));
    }

}

結果

排序之前：
[21, 30, 49, 30*, 16, 9]
開始排序
[9, 30, 21, 30*, 16, 49]
[16, 30*, 21, 9, 30, 49]
[9, 16, 21, 30*, 30, 49]
[9, 16, 21, 30*, 30, 49]
[9, 16, 21, 30*, 30, 49]
排序之後：
[9, 16, 21, 30*, 30, 49]