字符集合s={s1,s2,s3,s4,s5,s6,s7};p={0.20,0.19,0.18,0.17,0.15,0.10,0.01}(其中,p 为s中各信源出现的频率)。用上述信源概率分布构造二元的Huffman编码器和译码器。