soujava-threads-FibonacciIterate.java

package forkjoin;

import java.math.BigInteger;

public class FibonacciProblem3 {

	BigInteger n;

	public FibonacciProblem3(int n) {
		this.n = BigInteger.valueOf(n);
	}
	
	public BigInteger solve() {	
		return fibonacci(n);
	}

	private BigInteger fibonacci(BigInteger n) {
		BigInteger previous = BigInteger.valueOf(-1), result = BigInteger.ONE;
		
		for (long i = 0; BigInteger.valueOf(i).compareTo(n) <= 0; i++) {
			BigInteger sum = result.add(previous);
			previous = result;
			result = sum;
		}
		
		return result;
	}

	public BigInteger getN() {
		return n;
	}
}