With respect to finding the first K simple paths, Yens algorithm [8] ran in O(K|V|3) time for a general network, where |V| is the number of nodes. Katoh et al. [9] improved the time to be O(K(|A| + |V|log|V|)), where |A| is the number of arcs. Hadjiconstantinou and Christofides [10] presented an efficient implementation for finding a large number of simple paths based on Katoh et al. [9]. Finding K simple paths for a network with time–schedule or time–window constraints can be found in [11,7].