“…The unique knapsack problem (UKP) has been given considerable attention in the literature though it is not, in fact, as difficult as (MKP), more precisely, it can be solved in a pseudo-polynomial time (see [2,3,6,11,12]). We have then tried to transform the original (MKP) into a (UKP) (see also [15,17]). In this purpose, we have used a relaxation technique, that is to say, surrogate relaxation.…”