The worst case runtime for creating a Huffman tree is occurred
if the probability of the symbol overreach 2(-1) =0.5 ,
this will make upper limits of the incompetency limitless i.e if
the probability of characters are more in the input text then it
would produce bad compression.
Huffman tree for N characters and the run time to combine the
trees is O(nlogn) and also it requires O(logn) to determine the
less weight and insert new weight in the iteration of huffmans
tree.