Mathematical Problems in Engineering

Research Article

A Hybrid GRASP+VND Heuristic for the Two-Echelon Vehicle Routing Problem Arising in City Logistics

Algorithm 2

Procedure split for a random permutation of all customers.
)     ; ;
( )    for     to     do
( )       ; ; ;
( )    end for
( )    for     to     do
( )       load  ← 0; cost1 ← 0; ;
( )       repeat
( )       load ←load + ;
( )       if     then
( )       cost1 ← 0;
( )    else
( )      cost1 ← cost1 + ;
( )   end if
( )   cost ←cost1 + min ; Record the best satellite ;
( )   if  load ≤   then
( )      if     then
( )          ; + cost;
( )          ; ;
( )    end if
( )    if ( ) and ( + cost < ) then
( )        + cost; ; ;
( )    end if
( )     ;
( )   end if
( )   until ( ) or (load > )
( ) end for
( ) Using vectors and , return the resulting set Trips of second-level routes