For eg: consider a worst case input of 2 list.
1,3,5 and 2,4,6 - when we 'merge' them using merge function we only requires 5 comparisons(6-1) to form 1 2 3 4 5 6.
In the main question ,lets name the 16 element sorted lists as A,B,C,D
A and B are combined - 31 comparisons( 32-1)
C and D -31 comparisons
then AB and CD are combined (64-1 =63 comparisons) (AB and CD are combined list of 32 elements each).
So total comparisons 31+31+63=125
Thats the logic I followed.
I dont see how they are getting the value of '2n-3'. I am getting 'n-2' when I solve that equation,
