Page one is the algorithm and page 2 is an example.
Off the example, I understand that the the Freq column is organised in descending order then the bottom probabilities are added then the number 8 is brought up to join the 0. But the third column confuses me... how come the 7 is brought down? also the same for the 4th part where the 2 is brought down? Then the 4 and 3 are brought down in the next part?
Also why on the 4th last 6 and 3 is put straight to the top? Why is this?
I cant see the reasons for this mentioned in the algorithm.