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

The problem is that because you are using simple recursion, you re-evaluate F(n) multiple times, so your execution time is exponential.

There are two simple ways to fix this:

1) Cache values of F(n) when they are evaluated the first time. Check the cache first before evaluating F(n) to see if you have already calculated it for this n.

2) Use an iterative approach: Calculate F(1), F(2), F(3), etc... until you reach the number you need.