In 2002 I invented the Trie data structure. <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Trie" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Trie</a><p>I used it in a programming competition to very quickly count and sort the words in a book.