public class HeapSort {
public static void heapSort(DataWraper[] data){
System.out.println("開始排序");
int arrayLength=data.length;
//循環建堆
for(int i=0;i<arrayLength-1;i++){
//建堆
buildMaxHeap(data,arrayLength-1-i);
//交換堆頂和最后一個元素
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(最后一個節點)的父節點開始
for(int i=(lastIndex-1)/2;i>=0;i--){
//k保存正在判斷的節點
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小于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節點的值小于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循環的下一次循環,重新保證k節點的值大于其左右子節點的值
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("排序之后:/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]
排序之后:
[9, 16, 21, 30*, 30, 49]
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