Given a set of itEMS, each with a cost and a value, determine the number of each item to include in a collection so that the total cost is less than some given cost and the total value is as large as possible. The 0/1 knapsack problem restricts the number of each itEMS to zero or one. Such constraint satisfaction problEMS are often solved using dynamic programming. The general knapsack problem is NP-hard, and this has led to attempts to use it as the basis for public-key encryption systEMS. Several such attempts failed because the knapsack problEMS they produced were in fact solvable by polynomial-time algorithms. [Are there any trusted knapsack-based public-key cryptosystEMS?]. (1995-04-10)