算法导论---堆排序Java代码实现

package Search;
//堆排序算法实现
public class HeapSort1 {

public static void main(String[] args) {

	int arr[] = { 4, 1, 3, 2, 16, 9, 10, 14, 8, 7 };

	HeapSort1 hs1 = new HeapSort1();
	
	hs1.HeapSort(arr,arr.length);
	hs1.Print(arr);
}


//节点i的父亲节点是i/2
public int Parent(int i) {
	return i / 2;
}

//节点i的左孩子2i
public int Left(int i) {
	return 2 * i;
}

//节点i的右孩子2i+1
public int Right(int i) {
	return 2 * i + 1;
}


//维护堆的性质，使之永远保持是一个最大堆
public void MaxHeapify(int arr[], int i,int heapsize) {
	int largest = 0;//记录最大的节点，使之放在根节点
	int l = Left(i);
	int r = Right(i);
	if (l <= heapsize-1 && arr[l] > arr[i]) {
		largest = l;
	} else
		largest = i;
	if (r <= heapsize-1 && arr[r] > arr[largest]) {
		largest = r;
	}
	if (largest != i) {
		int temp = arr[i];
		arr[i] = arr[largest];
		arr[largest] = temp;
		MaxHeapify(arr,largest,heapsize);
	}

}


//维护堆的性质，使之永远保持是一个最小堆

// public void MinHeapify(int arr[], int i,int heapsize) {
// int smallestest = 0;//记录最小的节点，使之放在根节点
// int l = Left(i);
// int r = Right(i);
// if (l <= heapsize-1 && arr[l] // smallestest = l;
// } else
// smallestest = i;
// if (r <= heapsize-1 && arr[r] < arr[smallestest]) {
// smallestest = r;
// }
// if (smallestest != i) {
// int temp = arr[i];
// arr[i] = arr[smallestest];
// arr[smallestest] = temp;
// MaxHeapify(arr,smallestest,heapsize);
// //MinHeapify(arr,smallestest,heapsize);
// }
//
// }
//建队
public void BuildMaxHeap(int arr[],int heapsize) {
for (int i =(arr.length-1 )/ 2 ; i >= 0; i–) {
MaxHeapify(arr,i,heapsize);
//MinHeapify(arr,i,heapsize);
}
}

//排序算法
public void HeapSort(int arr[], int heapsize) {
	BuildMaxHeap(arr,heapsize);
	for (int i = arr.length-1; i > 0; i--) {
		int temp = arr[0];
		arr[0] = arr[i];
		arr[i] = temp;
		heapsize = heapsize - 1;
		MaxHeapify(arr,0,heapsize);
		//MinHeapify(arr,0,heapsize);
	}

}


//打印
public void Print(int arr[]) {
	for (int i = 0; i < arr.length; i++) {
		System.out.print(arr[i]+" ");
	}
}

}