characters have the smallest codes and longer codes for least frequent characters. There are mainly two parts. First one to create a Huffman tree, and another one to traverse the tree to find codes. However, Huffman coding is usually faster and arithmetic coding was historically a subject of some concern over patent issues. Thus many technologies have historically avoided arithmetic coding in favor of Huffman and other prefix coding techniques. As of mid-2010, the most commonly used techniques for this alternative to Huffman coding have passed into the public domain as the early patents have expired.