代码如下:
import java.util.Arrays;
public class HeapSort {
public static void heapSort(DataWraper[] data){
System.out.println("开始排序");
int arrayLength=data.length;
//循环建堆
for(int i=0;i<arrayLength-1;i++){
//建堆
buildMaxHeap(data,arrayLength-1-i);
//交换堆顶和最后一个元素
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;
}
//对data数组从0到lastIndex建大顶堆
private static void buildMaxHeap(DataWraper[] data, int lastIndex) {
// TODO Auto-generated method stub
//从lastIndex处节点（最后一个节点）的父节点开始
for(int i=(lastIndex-1)/2;i>=0;i--){
//k保存正在判断的节点
int k=i;
//如果当前k节点的子节点存在
while(k*2+1<=lastIndex){
//k节点的左子节点的索引
int biggerIndex=2*k+1;
//如果biggerIndex小于lastIndex，即biggerIndex+1代表的k节点的右子节点存在
if(biggerIndex<lastIndex){
//若果右子节点的值较大
if(data[biggerIndex].compareTo(data[biggerIndex+1])<0){
//biggerIndex总是记录较大子节点的索引
biggerIndex++;
}
}
//如果k节点的值小于其较大的子节点的值
if(data[k].compareTo(data[biggerIndex])<0){
//交换他们
swap(data,k,biggerIndex);
//将biggerIndex赋予k，开始while循环的下一次循环，重新保证k节点的值大于其左右子节点的值
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("排序之后：\n"+Arrays.toString(data));
}
}
结果：
排序之前：
[21, 30, 49, 30*, 16, 9]
开始排序
[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]
排序之后：
[9, 16, 21, 30*, 30, 49]