Java详细讲解堆排序与时间复杂度的概念

import java.util.Arrays;
public class Sort {
     //将任意数组进行原地堆排序
    public static void heapSort(int[] arr) {
        //把数组调整为最大堆，从最后一个非叶子节点开始下沉
        for (int i = (arr.length-1-1)/2; i >= 0; i--) {
            siftDown(arr,i,arr.length);
        }
        //将堆顶元素和最后一个元素交换
        for (int i = arr.length-1; i > 0 ; i--) {
            swap(arr,0,i);
            siftDown(arr,0,i);
        }
    }
   //下沉操作
    private static void siftDown(int[] arr, int i, int n) {
        while ((2 * i)+1 < n){
            int j = (2 * i) + 1;
            if(j+1<n && arr[j+1]>arr[j]){
               j = j+1;
            }
            if(arr[i] >= arr[j]){
                break;
            }else{
                swap(arr,i,j);
                i = j;
            }
        }
    }
     public static void main(String []args){
        int []arr = {7,6,7,11,5,12,3,0,1};
        System.out.println("排序前："+ Arrays.toString(arr));
        heapSort(arr);
        System.out.println("排序后："+Arrays.toString(arr));
    }
}