pranet's blog

By pranet, history, 4 years ago, In English,

I was trying to implement the following functions on a N * N grid in O(log^2(N)) time:

  1. Update: Add v to all grid points in specified rectangle. (v, rectangle are specified in this update)

  2. Query: Print maximum value in specified rectangle. (rectangle is specified in this query)

I tried implementing a 2-D segment tree, but got stuck with the range updates part (lazy propagation in 2-D dimensions is not pretty)

Is it even possible to do so? (anything below O(N) per operation is fine).

 
 
 
 
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P.S. lazy propagation does not work in 2D as far as I know

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Old thread about this problem. It seems to be really hard (or impossible?) to do this in time per query.