“…Most local search methods using the legal strategy jointly rely on two or three of these move operators. For instance, methods that employ the add and drop moves include the tabu search algorithms (Gendreau, Soriano, & Salvail, 1993), the RLS algorithm (Battiti & Protasi, 2001) and the KLS algorithm (Katayama, Hamamoto, & Narihisa, 2005) while examples of using all three moves (add, drop and swap) are the VNS algorithm (Hansen, Mladenović, & Uroševié, 2004), the family of PLS (Pullan, 2006), DLS (Pullan & Hoos, 2006), CLS (Pullan, Mascia, & Brunato, 2011) algorithms, the MN/TS algorithm (Wu, Hao, & Glover, 2012), the BLS algorithm (Benlic & Hao, 2013) and the SBTS algorithm (Jin & Hao, 2015). Notice that in some rare cases, more general swap(a, b) could be also useful allowing to exchange a and b vertices between C and V \ C.…”