Java Program Fibonacci Sequence

Question

I am writing a \"simple\" program to determine the Nth number in the Fibonacci sequence. Ex: the 7th number in the sequence is: 13. I have finished writing the program, it

Answer 1

There are a number of solutions. The most straightforward is to use memoization. There's also Binet's formula which will give you the nth fibonacci number in constant time.

For memoization, you store your results for F[a_i] in a map or list of some kind. In the naive recursion, you compute F[4] hundreds of thousands of times, for example. By storing all these results as you find them, the recursion ceases to proceed like a tree and looks like the straightforward iterative solution.

If this isn't homework, use Binet's formula. It's the fastest method available.