Approximation Algorithms for the Incremental Knapsack Problem via Disjunctive Programming
arXiv:1311.4563
Abstract
In the incremental knapsack problem ($\IK$), we are given a knapsack whose capacity grows weakly as a function of time. There is a time horizon of periods and the capacity of the knapsack is in period for . We are also given a set of items to be placed in the knapsack. Item has a value of and a weight of that is independent of the time period. At any time period , the sum of the weights of the items in the knapsack cannot exceed the knapsack capacity . Moreover, once an item is placed in the knapsack, it cannot be removed from the knapsack at a later time period. We seek to maximize the sum of (discounted) knapsack values over time subject to the capacity constraints. We first give a constant factor approximation algorithm for $\IK$, under mild restrictions on the growth rate of (the constant factor depends on the growth rate). We then give a PTAS for $\IIK$, the special case of $\IK$ with no discounting, when .
Key words: Approximation Algorithms, Integer Programming, Disjunctive Programming