the structure of employees is in the form of binary search tree and you
have to find the cost of transfering message from one employee to the
other employee

is this enough?

I got that :)) But I could not understand how the costs are formed. I
mean, how 1 15 is 8 (that is posted on the webboard) and such
stuff.... what are the prices of transferring one message from one
employee to another? That's what I couldn't get

first of all , draw the binary search tree of 1-15 in your paper and look
at it along with the explaination

1 to 2 : 0 : they are direct subordinate and superior
2 to 3 : 0 : direct superior and subordinate
3 to 4 : 1 : 3 have to send to 2 to have 4 get the message
4 to 5 : 1 : have to pass 6
5 to 6 : 0 : again, direct
6 to 7 : 0
and this is a important part to make you really understand: 7 to 8 : 2 :
have to pass to 6 and then 4 to have 8 have the message
you sould understand now if my english is not too bad
anyway
8 to 9 : 2
9 to 10 : 0
10 to 11 : 0
11 to 12 : 1
12 to 13 : 1
13 to 14 : 0
14 to 15 : 0
and total is 8