“…Finally, they go right to the seventh subarea to serve customers from left to right and go up to the eighth to serve customers from right to left and go back to the warehouse. Now, we obtain the service sequence codes as {18, 1,3,7,9,19,6,12,16,8,14,2,13,15,20,11,17,4,5,10} (Figure 1). en, we randomly generate the group codes as {2,5,3,4,5,1}.…”