单线程版本，改变递增式获取结果的算法

ImprovedFibonacci.java

package com.learn.jsry166y.demo;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;

/**
 * 单线程版本，改变递增式获取结果的算法
 * @author yongboy
 * @time 2012-1-30
 * @version 1.0
 */
public class ImprovedFibonacci {
	private static final int[] resultsArray = { 1, 1, 2, 3, 5, 8, 13, 21, 34,
			55, 89 };
	public static final List<Long> results = new ArrayList<Long>();
	static {
		for (int i : resultsArray) {
			results.add(Long.valueOf(i));
		}
	}

	final int n;

	ImprovedFibonacci(int n) {
		this.n = n;
	}

	private long compute(int small) {
		return results.get(small);
	}

	public Long compute() {
		if (n <= resultsArray.length) {
			return compute(n);
		}
		
		int index = -1;
		while(n >= (index = results.size())){
			results.add(compute(index - 2) + compute(index - 1));
		}
		
		return compute(index-1);
	}

	public static void main(String... args) throws InterruptedException,
			ExecutionException {
		long start = System.currentTimeMillis();
		ImprovedFibonacci fjt = new ImprovedFibonacci(12);
		System.out.println(fjt.compute());

		System.out
				.println("use time : " + (System.currentTimeMillis() - start));
	}
}