What is meant by cumulative frequency in binary index tree? And how is it needed to support dynamic arithmetic data compression?

Here is the link from which i am learning Binary Index Tree. ‘binary indexed tree’.

Frequency is how often something happens. Let’s say there are seven A letters in a text. That’s its frequency f(‘A’) = 7. I assume that is the case, since you are studying compression.

Cumulative frequency (of a tree node) would be sum of (cumulative) frequencies of it’s children, I would asume. The Figue 2 seems to support the notion - the height of the bar represent (cumulative) frequency I think.

Sorry, won’t help you with this particular paper/data-structure.

Brother I dont know what cumulitive freq in Fenwick tree all about, but here is a link in which you can learn it quite well. link

Good Luck