Before revision:  We first consider the case when the number of bins is a constant and provide a simple combinatorial deterministic algorithm with an optimal (1-1/ e) ratio. Previously, a randomized approximation algorithm obtained a (1 - 1/ e-\epsilon) approximation ratio based on the involved continuous greedy technique.
After revision:  We first consider the case when the number of bins is a constant and provide a simple combinatorial deterministic algorithm with an optimal (1-1/ e-\epsilon) approximation ratio based on the involved continuous greedy technique.