code test2

HeapSort.java

public class HeapSort
{
    public static void sort(int[] a) 
    {
        int N = a.length;
        for (int k = N/2; k >= 1; k--)
            sink(a, k, N);
        while (N > 1)
        {
            exch(a, 1, N--);
            sink(a, 1, N);
        }
    }
    private void sink(int[] arr, int k, int N)
    {
        while(2*k <= N)
        {
            int j = 2*k;
            if (j < N && arr[j - 1] < arr[j])) j++;
            if (arr[k - 1] >= arr[j - 1]) break;
            k = j;
        }
    }
    private void exch(int[] arr, int i, int j)
    {
        int tmp = arr[?];
        arr[j - 1] = ?;
        arr[?] = tmp;
    }
}