Aspects of the disclosure provide an apparatus that includes a key generator, a first memory, a second memory, and a controller. The key generator is configured to generate a first search key, and one or more second search keys in response to a pattern. The first memory is configured to compare the first search key to a plurality of entries populated in the first memory, and determine an index of a matching entry to the first search key. The second memory is configured to respectively retrieve one or more exact match indexes of the one or more second search keys from one or more exact match pattern groups populated in the second memory. The controller is configured to select a search result for the pattern from among the index output from the first memory and the one or more exact match indexes output from the second memory.