unpack, pack

[Hen Hanna]

when i unpack  the string (or Seed)    USENEARSEYNE   , 
                 i get    words like           Sense,  Sears, ........, Snare, Unary, ....
 (sarsen, seesee, senary, serene, unease, uneasy, usneae, usneas)
 (sensyne)



How would i approach  the PACKING  function ?

e.g. ...   i want to find the string  X  that packs
                Apple,  Pie,  Apricot,  Banana,  Candy

                  (packing doesn't require an English dictionary)

and i want X to be short.              Thanks!

                              (is this in Vol.3 of Knuth?)