Consider the problem  $\max_x \;||x||_2\\ x\in P\subseteq \mathbb{R}_{\geq 0}^n$where $||\cdot||$ is Euclidean 2-norm and $P$ is a polytope in positive orthant of $\mathbb{R}^n$. Is this problem computationally hard?
Complexity of max problem
cc.complexity theory;complexity classes;convex optimization