Thank you!

Thank you for the great cata!
Your reference solution in JavaScript does not always find all optimal solutions by steps.
Example:

  #    #  #     #    
    #        #       
      #  x     ##  ##
  E    #      #    # 
#    #  #   x#   #   
##   #   #x#     #  #
     #  # #   ## S   
           ##        
       x    #    #  #
      x            x 
    x  x x           
     #       # # # ##
   #   #   # x## x  #
#     # #        #   
# #      x   ###     
 x    #   x     #x # 
  #      # #  # #   
      #    #  # #    
##   # # #        # #

Possible optimal solutions (sorted by length):
dldrullul (length: 40)

Your solution: dldlllurdl (length: 30)

 # #     ##      #   #  
     #   #x  # # #      
##   # #  # #     #    #
#   # #                 
     #        # #       
              #x   # #  
x   #           ##      
 #           xx#  S  x#x
  #  #        ## # x  x 
  x      # #    ##   ##E
x           ## # # #  xx
            #        ## 
  # xx          x #  #x 
#     #          #  x   
              #    #  #x
  x         # x  x#  ## 
#     #   #     x#      

Possible optimal solutions (sorted by length):
urdd (length: 15)

Your solution: rdrrd (length: 7)