“…Caserta, Schwarze, and Voß (2012) prove that the blocks relocation problem with and without Assumption A1 is NP-hard. Several heuristic solution approaches exist which are mainly based on branch and bound procedures or tree search (Caserta, Schwarze, & Voß, 2009;Caserta, Voß, & Sniedovich, 2011;Forster & Bortfeldt, 2012;Jin, Zhu, & Lim, 2015;Jovanovic & Voß, 2014;Kim & Hong, 2006;Rei & Pedroso, 2012;Ünlüyurt & Aydin, 2012;Wu, Hernández, & Ting, 2010;Zhang, Guo, Zhu, Lim, & Cheang, 2010;Zhu, Qin, Lim, & Zhang, 2012).…”