Is there a tree that can rank an object?

Question

I encoded the Red Black binary statistics tree to get the rank of an arbitrary object comparable to other objects in the Red Black tree. I wonder if there is an API class that provides the same functionality.

It would be nice if a rank were assigned, the class has a function that returns an object of this rank inside the tree.

Note that Red-black BST allows these two operations in log (n) time, where n is the number of objects in the tree.

Answer 1

The standard API does not have an order statistics tree. TreeMapin particular, it does not have methods for searching for the rank of a key or finding a key by rank in O (log n) time.

( Apache Commons, Google Guava) .

Answer 2

http://algs4.cs.princeton.edu/33balanced/RedBlackBST.java.html.

Prof. Sedgewick RedBlack, , , RedBlack BST. ( O (lgN)). ( , ). . ( java.util )

Answer 3

. TreeMap<YourClassAsKey, Long>, TreeMap BST Long .

javadoc:

NavigableMap Red-Black.

Answer 4

, TreeMap:

NavigableMap Red-Black. , , , .

log (n) containsKey, get, put remove. - , Cormen, Leiserson Rivest. .

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, , , .

NavigableMap ( TreeMap) , floorKey ceilingKey.