java retain information in recursive function

Question

Is it possible to retain information via a helper function with java, without using static variables.

For example,

public void foo(){
    int v = 0;
         


        

Answer 1

I think this is called memoization. It looks like

class Fibonacci
{
     public Map < Integer , Integer > memorized = new HashMap < > ( ) ;

     public int fib ( int n )
     {
           if ( memoized . containsKey ( n ) )
           {
                 return memoized . get ( n ) ;
           }
           else
           {
                 int fib = // calculate recursively
                 memoized . put ( n , fib ) ;
                 return fib ;
           }
     }
}

You should be able to get decent (not optimal) performance out of this algorithm. The primary reason that the recursive fibonacci algorithm has horrible performance is b/c it is repeatedly calculating the same values. With recursion+memoization it never calculates any value more than once.

Thanks to @Aristide for pointing out the subtle difference between memorization and memoization.