HuffmanCode(T):
|  Input  string T of size n
|  Output optimal encoding tree for T
|
|  compute frequency array
|  Q=new priority queue
|  for all characters c do
|  |  T=new single-node tree storing c
|  |  join(Q,T) with frequency(c) as key
|  end for
|  while |Q|≥2 do
|  |  f1=Q.minKey(), T1=leave(Q)
|  |  f2=Q.minKey(), T2=leave(Q)
|  |  T=new tree node with subtrees T1 and T2
|  |  join(Q,T) with f1+f2 as key 
|  end while
|  return leave(Q)