What is the special property of red-black trees and what root should always be?

Category: QuestionsWhat is the special property of red-black trees and what root should always be?
Editor">Editor Staff asked 4 weeks ago

What is the special property of red-black trees and what root should always be?
 
(a) a color which is either red or black and root should always be black color only
 
(b) height of the tree
 
(c) pointer to next node
 
(d) a color which is either green or black
 
I’m obligated to ask this question of Red Black Tree in chapter Binary Trees of Data Structures & Algorithms I
 
The question was asked in a job interview.

1 Answers
Editor">Editor Staff answered 4 weeks ago

Right option is (a) a color which is either red or black and root should always be black color only
 
The best explanation: An extra attribute which is a color red or black is used. root is black because if it is red then one of red-black tree property which states that number of black nodes from root to null nodes must be same, will be violated.