/*
 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
 * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Main.java to edit this template
 */
package bigintegerfibonacci;

import java.math.BigInteger;

/**
 *
 * @author caleb
 */
public class BigIntegerFibonacci {

    /**
     * @param args the command line arguments
     */
    private static BigInteger[] fibonacciCache;
    public static void main(String[] args) {
        int n = 100000;
        fibonacciCache = new BigInteger[n + 1];
        System.out.println("Calculating fibonacci for number " + n + "...");
        // Precache value to prevent stack overflow
        for (int i = 0; i <= n; ++i) {
            fibonacci(i);
        }
        System.out.println(fibonacci(n));
        
    }
    
    private static BigInteger fibonacci(int n) {
        // Base case
        int compareInt = BigInteger.valueOf(n).compareTo(BigInteger.ONE);
        //System.out.println("value is: " + compareInt);
        
        if (compareInt == -1 || compareInt == 0){
            return BigInteger.valueOf(n);
        }
        if (fibonacciCache[n] != null) {
            return fibonacciCache[n];
        }
        BigInteger nthFibNumber = (fibonacci(n - 1).add(fibonacci(n - 2)));
        fibonacciCache[n] = nthFibNumber;
        return fibonacciCache[n];
    }
    
}