大顶堆 Java部分实现

//java 大顶堆的简单实现
import java.util.Arrays;
public class Heap{
public void heapSort(int[] num){
int n = num.length;
for(int i = n/2;i>=0;i--){ //建堆，从n/2开始向上调整
adjustHeap(num, i, n);
}
for(int j=n-1;j>=0;j--){
swap(num,0, j); //交换开始和最后位置上的数字
adjustHeap(num, 0, j); //交换之后再调整堆
}
}
public void adjustHeap(int[] num,int s,int n){ //由于根节点编号是从0开始的，所以其左子树是2*i+1
for(int i=s;i<n;){
int max = i;
if((2*i+1)<n&&num[2*i+1]>num[max]) max = 2*i+1;
if((2*i+2)<n&&num[2*i+2]>num[max]) max = 2*i+2;
if(max!=i){
swap(num,i,max); 
i=max;
}else break;

}

}
public void swap(int[] num,int i,int j){
int tem = num[i];
num[i] = num[j];
num[j] = tem;
}
public static void main(String[] args) {
Heap heap = new Heap();
int[] num = new int[]{49,38,65,97,76,13,27,49};
heap.heapSort(num);
System.out.println(Arrays.toString(num));
}
}