An Algorithm for the Calculation of the Szeged Index of Benzenoid Hydrocarbons

The Szeged index (Sz) is a recently proposed1q2 structural descriptor, based on the distances of the vertices of the molecular graph. In order to be able to study the properties of this novel topological index it would be advantageous to possess an easy method for its calculation. The calculation of Sz directly from its definition (see below) is quite cumbersome, especially in the case of large polycyclic molecules. In this paper we put forward a procedure for computing Sz that is significantly simpler. The algorithm, in the form elaborated in this paper, applies to benzenoid molecules, but its extension to other types of polycyclic systems would easily be possible.