Directed travelling salesman problem
Barnali Chakrabarti · Journal of Physics A Mathematical and General · 1986
Considers an exactly soluble directed travelling salesman problem, where the salesman is forbidden to move, during its visit to the cities, opposite to a particular direction. When the cities are randomly distributed, with concentration p, on the sites of a square lattice of linear size L, the optimised total contour length becomes (1/p)+(2(2p-1)/p 2 ) (1/L) per city (p>0).