} else {
			r = c
		}
	}

	end := n - start
	if start < m && m < end {
		rotate_func(data, start, m, end)
	}
	if a < start && start < mid {
		symMerge_func(data, a, start, mid)
	}
	if mid < end && end < b {
		symMerge_func(data, mid, end, b)
	}
}

// rotate_func rotates two consecutive blocks u = data[a:m] and v = data[m:b] in data: