说明：  问题描述] 利用哈夫曼编码进行信息通信可以大大提高信道利用率，缩短信息传输时间，降低传输成本。但是，这要求在发送端通过一个编码系统对待传数据预先编码，在接收端将传来的数据进行译码（复原）。对于双工信道（即可以双向传输信息的信道），每端都需要一个完整的编/译码系统。试为这样的信息收发站写一个哈夫曼编/译码系统。
(Description of the problem] use Huffman encoding of information and communication can greatly improve the channel utilization, reduce the information transmission time, lower transmission costs. However, this requires the sending end through a coding system for pre-treatment of mass data encoding, will be heard at the receiving end of the data decoding (recovery). For duplex channel (ie, two-way transmission of information can be channel), each client requires a full encoder/decoder system. Test for such information transceiver station to write a Huffman encoder/decoder system.)