import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
import java.util.Random;
public class HeapSort {
public static void main(String[] args) {
// int[] arr = {4,6,8,5,9,2,7,10,-1,3};
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date date = new Date();
String dateStr = simpleDateFormat.format(date);
System.out.println(dateStr);
int count = 8000000;
int arr[] = new int[count];
Random random = new Random();
for (int i = 0; i < count; i++) {
arr[i] = random.nextInt();
}
heapSort(arr);
date = new Date();
dateStr = simpleDateFormat.format(date);
System.out.println(dateStr);
//System.out.println(Arrays.toString(arr));
}
public static void heapSort(int arr[]){
System.out.println("堆排序!!!");
// 先将树格式化成大顶堆
for(int i= arr.length/2-1; i>=0; i--){
adjustHeap(arr,i,arr.length);
}
//System.out.println("大顶堆:"+ Arrays.toString(arr));
for(int j=arr.length-1; j>=0; j--){
int temp = arr[j];
arr[j] = arr[0];
arr[0] = temp;
adjustHeap(arr,0,j);
}
//System.out.println(Arrays.toString(arr));
}
// 将一个数组,调整成一个大顶堆
public static void adjustHeap(int[]arr, int i, int length){
int temp = arr[i];
for(int k=2*i+1; k<length; k=k*2+1){
if(k+1 < length && arr[k] < arr[k+1]){
// 左子结点小于右子结点
k++;
}
if(arr[k] > temp){
arr[i] = arr[k];
i = k;
}else{
break;
}
}
arr[i] = temp;
}
}