  We investigate the following problem $$ -{\rm div}(v(x)|\nabla u|^{m-2}\nabla
u)+V(x)|u|^{m-2}u=
\Big(|x|^{-\theta}*\frac{|u|^{b}}{|x|^{\alpha}}\Big)\frac{|u|^{b-2}}{|x|^{\alpha}}u+\lambda\Big(|x|^{-\gamma}*\frac{|u|^{c}}{|x|^{\beta}}\Big)\frac{|u|^{c-2}}{|x|^{\beta}}u
\quad\mbox{ in }\R^{N}, $$ where $b, c, \alpha, \beta >0$, $\theta,\gamma \in
(0,N)$, $N\geq 3$, $2\leq m< \infty$ and $\lambda \in \R$. Here, we are
concerned with the existence of groundstate solutions and least energy
sign-changing solutions and that will be done by using the minimization
techniques on the associated Nehari manifold and the Nehari nodal set
respectively.
