Clarification on Red-Black tree .
'''Originally Posted By: ahmed93'''
I was looking at the slide http://www.cs.sjsu.edu/faculty/pollett/ ... 14.html#(7)<br>Shouldn't the black height of the top node with value 26 be 4 instead of 3 as it says on the slide.<br>It is slide 7
'''Originally Posted By: dburke'''
See the first bullet on that slide: the black count doesn't include the node itself
'''Originally Posted By: ahmed93'''
Yea i realize that but that node has 2 black nodes on the left side and 2black nodes on the right side. 14 and 7 on left and 41 47 on right
'''Originally Posted By: dburke'''
But you're not counting the number of black nodes in any sort of total, you're counting the number of black nodes in any path from the current node to a NIL leaf node. So if your current node is the root node (key value of 26), all the paths from the current node to a NIL leaf with have a black count of three: 41-47-NIL, 41-38-NIL, 14-7-NIL, 14-12-NIL, 14-16-NIL, 21-19-NIL, 21-23-NIL, 41-28-NIL, all these paths have a black count of 3, giving the root node it's black height of 3.
'''Originally Posted By: ahmed93'''
o ok got it thanks