other -= length
			}
			data.Swap(idx, a+other)
		}
	}
}

// choosePivot_func chooses a pivot in data[a:b].
//
// [0,8): chooses a static pivot.
// [8,shortestNinther): uses the simple median-of-three method.
// [shortestNinther,∞): uses the Tukey ninther method.
func choosePivot_func(data lessSwap, a, b int) (pivot int, hint sortedHint) {
	const (
		shortestNinther = 50