void
upheap(int *h, int k)
{
    int         v = h[k];

    while (k/2 > 0 && h[k/2] < v) {
        h[k] = h[k/2];
        k = k/2;
    }
    h[k] = v;
}

void
insert(int *h, int *pn, int v)
{
    h[++*pn] = v;
    upheap(h, *pn);
}

void
downheap(int *h, int n)
{
    int         v = h[1], k = 1, j;

    while (k <= n/2) {
        j = 2 * k;
        if (j < n && h[j] < h[j + 1]) j++;
        if (v > h[j]) break;
        h[k] = h[j];
        k = j;
    }
    h[k] = v;
}

int
delete(int *h, int *pn)
{
    int         v = h[1];

    h[1] = h[(*pn)--];
    downheap(h, *pn);
    return v;
}