killua123's blog

By killua123, history, 3 weeks ago, In English

I am new to range query data structures so i am treating fenwick tree as a black box. I know the working of fenwick but not able to code a 2d one.

I asked chatgpt for help it is giving wrong code I want it similar to this template so if anyone can help me with it.

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3 weeks ago, # |
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Because the problem allows for $$$O(N^2)$$$ memory, just put a Fenwick tree in every single node of a Fenwick tree to make it 2-dimensional.

Untested code

This will allow for point update and range query in $$$O(log^2\,N)$$$ time for both.