In case of matrix expo method of fibonacci the matrix will look like {{a+b,b},{b,a}} if f(0)=a and f(1)=b?? I didn’t get the clear concept about that matrix.
i would suggest you to read this ,it will clear all your doubts http://zobayer.blogspot.in/2010/11/matrix-exponentiation.htmllink text
https://www.hackerrank.com/contests/infinitum10/challenges/fibonacci-finding-easy … question from ongoing contest…