in the exercise 9 of the pdf ...how did they calculated path length i+j-2 ...and moreover it if possible please derive it in easy way with explanation.....
they mention that i means a node in level i and j means a node in level j and root node is at level 1
every time i wants to communicate j ===> i to root and root to j
distance between i to root ---> maximum edges btw them ===> i-1
distance between root to j ===> j-1
i wants to communicate j ==> (i-1)+(j-1) = i+j-2