1. A method comprising: receiving, by a computing device, a request to store an input value in a data structure, wherein the data structure stores one or more index values of a first group of index values, wherein the first group of index values uniquely represent storage values, wherein the one or more index values comprise a first group of representations of the storage values; determining, by the computing device, that the input value is not represented by an existing index value of the first group of index values; generating, by the computing device, an index value that represents the input value; determining, by the computing device, that the generated index value is not included in the first group of representations; responsive to determining that the generated index value is not included in the first group of representations, generating, by the computing device, a second group of index values comprising a second group of representations that uniquely represent all of the storage values and the input value, wherein a first size of index values of the first group is different than a second size of index values of the second group; modifying, by the computing device, a storage capacity of the data structure to store the index values of the second group of the second size; and storing, by the computing device, the second group of index values in the data structure.