class ShellSort extends SortAlgorithm {
    void sort(int a[]) {
	    int i, j, h; int v; 
		for (h = 1; h < a.length/9; h = 3*h+1) ;
		for ( ; h > 0; h /= 3) {
			for (i = h; i < a.length; i++) {
				v = a[i]; j = i;
				while (j >= h && a[j-h] > v)
					{ a[j] = a[j-h]; j -= h;  }
				a[j] = v;
				pause();
			}
		}
	}
}