         ------  ----
            A       10
            B       0
            C       110
            D       111

         I.e., 0 precedes 10 which precedes 11x, and 110 and 111 are
         lexicographically consecutive.

         Given this rule, we can define the Huffman code for an alphabet
         just by giving the bit lengths of the codes for each symbol of
         the alphabet in order; this is sufficient to determine the
         actual codes.  In our example, the code is completely defined
  