堆排序
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
class HeapSort {
public static void main(String[] args) {
int[] arr = new int[80000000];
for (int i = 0; i < 80000000; i++) {
arr[i] = (int) (Math.random() * 8000000);
}
System.out.println("排序前");
Date data1 = new Date();
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String date1Str = simpleDateFormat.format(data1);
System.out.println("排序前的时间是=" + date1Str);
heapSort(arr);
Date data2 = new Date();
String date2Str = simpleDateFormat.format(data2);
System.out.println("排序前的时间是=" + date2Str);
}
public static void heapSort(int arr[]) {
int temp = 0;
System.out.println("堆排序!!");
for(int i = arr.length / 2 -1; i >=0; i--) {
adjustHeap(arr, i, arr.length);
}
for(int j = arr.length-1;j >0; j--) {
temp = arr[j];
arr[j] = arr[0];
arr[0] = temp;
adjustHeap(arr, 0, j);
}
}
public static void adjustHeap(int arr[], int i, int lenght) {
int temp = arr[i];
for(int k = i * 2 + 1; k < lenght; k = k * 2 + 1) {
if(k+1 < lenght && arr[k] < arr[k+1]) {
k++;
}
if(arr[k] > temp) {
arr[i] = arr[k];
i = k;
} else {
break;
}
}
arr[i] = temp;
}
}