T(a,b) = complexity
         of MYSTERY

O(1)
O(b-a)
O(1)
max(T(a, c-1), T(c+1, b))

T(a, c-1) is largest when
	c-1 largest
	-> c = b-1
T(a, b-2)

T(c+1, b) is largest when
	c+1 smallest
	-> c = a

T(a+1, b)
T((n+1)/2)

worst case
b-a calls to mystery
O(b-a) complexity per call

total complexity
O((b-a)^2) = O(n^2)