Under what circumstances could a Huffman tree of ASCII characters generate a 2-bit code for some character? Under what circumstances could it generate a 20-bit code? Show that, if the symbols have...

Under what circumstances could a Huffman tree of ASCII characters generate a 2-bit code for some character? Under what circumstances could it generate a 20-bit code? Show that, if the symbols have already been sorted by frequency, Huffman’s algorithm can be implemented in linear time.