  Beyond the two-state case, the optimal state distinguishing is solved only in
a limited number of cases exhibiting a high degree of symmetry. With the use of
$\mathcal{PT}$-symmetric quantum mechanics, we provide an algorithm for an
unambiguous distinguishing of three pure quantum states by at most two
measurements without any additional restrictions on geometry and symmetry
possession of these states. We do not require any assumptions beyond those from
when distinguishing two quantum states. Thus we extend the
$\mathcal{PT}$-symmetric quantum state discrimination approach for the case of
three quantum states.
