Maximum number of characters using keystrokes A, Ctrl+A, Ctrl+C and Ctrl+V

Question

This is an interview question from google. I am not able to solve it by myself. Can somebody shed some light?

Write a program to print the sequence of keystrokes suc

Answer 1

Using the tricks mentioned in answers above, Mathematically, Solution can be explained in one equation as,

4 + 4^[(N-4)/5] + ((N-4)%5)*4^[(N-4)/5]. where [] is greatest integer factor