(1) Initialize the ps, , bat population and other parameters;
(2) Construct initial bat population;  // (3.3 Initialization construction)
(3) Assign landing time and evaluate each individual; // (3.2 Landing time assignment)
(4) repeat
(5)  for   :ps do
(6)    Determine frequency ;
(7)    Update each bat individual;
(8)  end
(9)  Assign landing time and evaluate each individual; // (3.2 Landing time assignment)
(10) if     then
(11)  Carry out swap local search operation;
(12) else
(13)  Carry out LSI local search operation;
(14) end
(15) Assign landing time and evaluate each individual; // (3.2 Landing time assignment)
(16) Compute loudness of each individual by (12);
(17) for   :ps do
(18)   if     then
(19)   Carry out RB operation; // Runway balance operation
(20)   else
(21)   Assign each aircraft to a random runway;
(22)   end
(23) end
(24) Assign landing time and evaluate each individual; // (3.2 Landing time assignment)
(25) until  
(26) Output result and plot
Algorithm 1: The pseudo-code of HBA for ALP.