Hash tables and k-mer set clusters. The left panel shows schematic of an example hash table (Hash table 1). Each key is a k-mer (k-mer-1, k-mer-2,..., k-mer-7) with an entry storing a list of numeric identifiers for the sequences with the k-mer substring. The upper right panel shows the second hash table (Hash table 2), where each key is the set of k-mers common among the set of vectors specified by the key. The bottom right panel shows the graph representation of the four k-mer sets (numbered 1 to 4) with k-mer sets as nodes and labeled edges between nodes representing shared vectors between nodes.