4 ms·

I believe Binet's formula is the fastest: http://www.maths.surrey.ac.uk/hosted-sites/R.Knott/Fibonacci/fibFormula.html http://www.maths.surrey.ac.uk/hosted-sit

• aprescott 8y ago
  The article mentions it. > There exist several closed-form solutions to Fibonacci sequence which gives us the > false hope that there might be an O(1) solution. Unfortunately they all turn out to > be non-optimal if you want an exact solution for a large n.