In this paper, a very fast capacitor assignment algorithm capable of finding an optimized decoupling solution scheme that meets a predefined target impedance for a given power distribution network (PDN) is presented. The algorithm provides an optimal combination of decap values and decap locations while minimizing the number of decoupling components needed to meet RL-type target impedances. The algorithm only takes a few seconds to find a decoupling solution even when there are a large number of models in the capacitor's libraries.