Question about WENO limiter
 

Hi.
These days I'm studying WENO limiter through following papers.
("Runge-Kutta discontinuous Galerkin method using WENO limiters" and
"RKDG method with WENO type limiters and conservative interfacial procedure for one-dimensional compressible multi-medium flow")

I have one question.
There are WENO reconstruction in the method.
(ex) if we use k(the order of polynomial in DG)=1,
we construct linear reconstruction polynomials p(x) and
a second degree reconstruction polynomial q(x).

In this case polynomial p(x) can be obtained easily. But polynomial q(x) is very complex to obtain.

I want to obtain polynomial q(x).

I would appreciate it if anyone give me some comments.

Thanks!!