Huffman coding is known to be optimal, yet its dynamic version may yield smaller compressed files. The best known bound is that the number of bits used by dynamic Huffman coding in order to encode a message of n characters is at most larger by n bits than the size of the file required by static Huffman coding. In particular, dynamic Huffman coding can also generate a larger encoded file than the static variant, though in practice the file might sometimes be smaller. We propose here a new variant of Huffman encoding, that provably always performs better than static Huffman coding by at least m − 1 bits, where m denotes the size of the alphabet, and may be better than the standard dynamic Huffman coding for certain files. The algorithm is based on reversing the direction for the references of the encoded elements, from pointing backwards into the past to looking forward into the future.

已知霍夫曼编码是最佳的，但其动态版本可能会产生较小的压缩文件。最著名的界限是，动态霍夫曼编码用于编码n个字符的消息所使用的位数最多比静态霍夫曼编码所需的文件大小大n位。特别是，动态霍夫曼编码还可以生成比静态变体更大的编码文件，尽管实际上该文件有时可能更小。我们在这里提出霍夫曼编码的新变体，证明它总是比静态霍夫曼编码好至少m − 1位，其中m表示字母的大小，并且可能优于某些文件的标准动态霍夫曼编码。该算法基于反转编码元素引用的方向，即从指向过去的过去到展望未来。