How to get the n-th value of a b-tree
Is there general pseudocode or related data structure to get the nth value of a b-tree? For example, the eighth value of this tree is 13 [1,4,9,9,11,11,12,13].
If I have some values sorted in a b-tree, I would like to find the nth value without having to go through the entire tree. Is there a better structure for this problem? The data order could update anytime.
You are looking for order statistics tree. The idea of it, is in addition to any data stored in nodes - also store the size of the subtree in the node, and keep them updated in insertions and deletions.
Since you are "touching" O(logn) nodes for each insert/delete operation - keeping it up to date still keeps the O(logn) behavior of these.
FindKth() is then done by eliminating subtrees that their bigger index is still smaller than k, and checking the next one. Since you don't need to go to the depth of each subtree, only directly to the required one (and checking the nodes in the path to this element) - you need to "touch" O(logn) nodes, which makes this operation O(logn) as well.
- Math.Sin() gives incorrect value
- How to run my python script when the sunOS is start booting
- Express-session: not resetting cookie expiration on each request
- Getting a stack overflow exception when normalizing a vector
- Edit default summary function in R gives error for multiple variables
- What was a For loop? Why isn't it needed in R?
- How to use download button in shiny and save results in various formats (csv, texte, pdf, spss...)?
- Why are there two assignment operators, `<-` and `->` in R?
- lm()$assign: what is it?
- How to get the value of list(...) in R and S functions
- Design matrix for MLM from library(lme4) with fixed and random effects
- how to generate elements not included in my sample
- Create a matrix with gradually changing values without a for loop
- Emacs ESS and S-plus ( S+ ) 8.1 compatability
- How to lag date-index in a time-series in R?
- Nonlinear regression in R / S
- Calling R from S-Plus?