heapsort(Java)(最小堆)

 public static void main(String[] args)
 {
     Scanner input = new Scanner(System.in);
     int n = input.nextInt();
     int[] a = new int[n];

     a[0] = 0;  //不使用第一个位置
     for(int i = 1; i < a.length; i++)
         a[i] = (int)(Math.random() * 100);
     //System.out.println(Arrays.toString(a));
     long start = System.currentTimeMillis();
     heapsort(a, a.length - 1);
     long end = System.currentTimeMillis();
     //System.out.println(Arrays.toString(a));
     System.out.println(end - start);
     //10000000个测试数据用时1050ms 100000000个测试数据用时11500ms
 }

 public void static heapsort(int[] a, int n)
 {
     for(int i = n / 2; i >= 1; i--)
     sink(a, i, n);
     while(n > 1)
     {
     int temp = a[n];
     a[n--] = a[1];
     a[1] = temp;
     sink(a, 1, n);
     }
 }

 public static void sink(int[] a, int k, int n)  //最小堆化
 {
     while(k <= n / 2)
     {
     int min_index = k * 2;
     if(min_index + 1 <= n && a[min_index + 1] < a[min_index])
         min_index++;
     if(a[k] > a[min_index])
     {
         int temp = a[k];
         a[k] = a[min_index];
         a[min_index] = temp;
         k = min_index;
     }
     else
         break;
     }
 }