One of the important basic tasks in computing is the finding of all occurrences of a particular alphanumeric string in a document, or the finding of all documents that have one or more occurrences of a given alphanumeric string. One common example where such a task needs to be carried out is on the World Wide Web, where search engine software needs to find all occurrences of a given query term or keyword, and return the results based on some rules of priority and relevance. It is also common for there to be find-and-replace macros or features in text-editing programs, allowing for all occurrences of a certain string to be replaced with another string. For example, in writing many form letters having the same nature, it is possible to just change the salutation: Dear Ms. Smith, Dear Mr. Jones, Dear Mrs. Fowler, Dear Dr. Koopman, etc...