霍夫曼编码解码。基本原理是频繁使用的数据用较短的代码代替，较少使用的数据用较长的代码代替，每个数据的代码个不相同。有时称之为最佳编码，一般就叫作Huffman编码。下面引证一个定理，该定理保证了按字符出现概率分配码长，可使平均码长最短。-Hoffman codec. Fundamental principle is frequently used data in lieu of using a short code, and less use of the data used in lieu of a longer code, each data source were different. Sometimes referred to as the best encoding, generally known as Huffman coding. The following quote a theorem, the theorem guarantees the emergence of the probability distribution of characters according to code length, allows the shortest average code length.