13. The storage medium of claim 12 , wherein the instructions to generate the digital document map table including at least one list of entries representing the digital documents comprises: determining whether any word stored in the word balanced tree is present in two or more digital documents stored in the digital document balanced tree; and interlinking two or more entries of the at least one entry in the at least one list of entries corresponding to the two or more digital documents stored in the digital document map table in a circular linked list fashion such that an entry associated with the first digital document points to an entry associated with a subsequent digital document including the word until an entry associated with a last digital document points back to one of the plurality of nodes in the word balanced tree representing the word.
13. The storage medium of claim 12 , wherein the instructions to generate the digital document map table including at least one list of entries representing the digital documents comprises: determining whether any word stored in the word balanced tree is present in two or more digital documents stored in the digital document balanced tree; and interlinking two or more entries of the at least one entry in the at least one list of entries corresponding to the two or more digital documents stored in the digital document map table in a circular linked list fashion such that an entry associated with the first digital document points to an entry associated with a subsequent digital document including the word until an entry associated with a last digital document points back to one of the plurality of nodes in the word balanced tree representing the word. 14. The storage medium of claim 13 , wherein the instructions to store the one or more extracted words in the word balanced tree further comprises: counting an occurrence of the word associated with the node of the word balanced tree in the set of digital documents of r one of the plurality of the nodes; determining whether the occurrence of the word associated with the node is greater than a predetermined occurrence threshold; restarting counting an occurrence of the word in another set of digital documents if the determined occurrence of the word associated with the node is greater than the predetermined occurrence threshold; and continuing the counting of the occurrence of the word in the set of digital documents until a number of occurrences of the word in the set of digital documents becomes equal to the predetermined occurrence threshold.