排序系列之堆排序

public class HeapSort {
public final static void heapSort(int a[]){
new MiniPriorityQueue(a);
}
private static class MiniPriorityQueue {
private final int queue[];
private int size;

public MiniPriorityQueue(int a[]) {
this.size = a.length;
this.queue = a;
heapify();
while(this.isNotEmpty()){
this.pop();
}
}
private void heapify() {
for (int i = (this.size >>> 1) - 1; i >= 0; i--)
siftDown(i, this.queue[i]);
}

private void siftDown(int index, int value) {
int i = this.size >>> 1;
while (index < i) {
int j = (index << 1) + 1;
int temp = this.queue[j];
int k = j + 1;
if ((k < this.size) && (this.queue[j] > this.queue[k])) {
temp = this.queue[(j = k)];
}
if (temp > value)
break;
this.queue[index] = temp;
index = j;
}
this.queue[index] = value;

}
public void pop(){
int result = this.queue[0];
int value = this.queue[--this.size];
siftDown(0, value);
this.queue[this.size]=result;
}
public boolean isNotEmpty(){
return this.size != 0;
}
}
public static void main(String[] args) {
int[] a= new int[]{5,3,7,8,2,6,1,4};
heapSort(a);
System.out.println(Arrays.toString(a));
}
}