public void quickSort(int[] a, int begin, int end) {
		int left = begin;
		int right = end;
		int temp = a[left];
		while (left < right) {
			while (left < right && a[right] >= temp)
				right--;
			if (left < right)
				a[left] = a[right];
			while (left < right && a[left] < temp)
				left++;
			if (left < right)
				a[right] = a[left];
		}
		a[left] = temp;
		if (left - begin > 1)
			quickSort(a, begin, left - 1);
		if (end - left > 1)
			quickSort(a, left + 1, end);
	}