Fibonacci Sequence in Java taking too long?

Question

I\'m trying to find the sum of the Fibonacci sequence in Java, but the run time is taking way too long (or is it suppose to?). This slows down anytime I use an integer past

Answer 1

You need to use long instead of int if you want to calculate the 50th Fibonacci number. The 50th Fibonacci number is 12586269025 and exceeds the maximum value of int (see http://www.maths.surrey.ac.uk/hosted-sites/R.Knott/Fibonacci/fibtable.html).

A non-recursive algorithm is likely going to be faster, see http://planet.jboss.org/post/fibonacci_sequence_with_and_without_recursion for the different implementations.