In Example we have shown how the tree develops when the sequence a a r d v is transmitted. Continue this example with the next letters in the sequence, ark.
Example
Updafe procedure Assume we are encoding the message [a a r d v a r k], where our alphabet consists of the 26 lowercase letters of the English alphabet. The updating process is shown in given Figure. We begin with only the NYT node. The total number of nodes in this tree will be 2 x 26 - 1 = 51, so we start numbering backwards from 51 with the number of the root node being 51. The first letter to be transmitted is a.
As a does not yet exist in the tree, we send a binary code 00000 for a and then add a to the tree. The NYT node gives birth to a new NYT node and a terminal node corresponding to a. The weight of the terminal node will be higher than the NYT node, so we assign the number 49 to the NYT node and 50 to the terminal node corresponding to the letter a. The second letter to be transmitted is also a. This time the transmitted code is 1.
The node corresponding to a has the highest number (if we do not consider its parent), so we do not need to swap nodes. The next letter to be transmitted is r. This letter does not have a corresponding node on the tree, so we send the code word for the NYT node, which is 0 followed by the index of r, which is 10001. The NYT node gives birth to a new NYT node and an external node corresponding to r.
Again, no update is required. The next letter to be transmitted is d, which is also being sent for the first time. We again send the code for
