【基础算法】- 个人认为最快的 Fibonacci 程序

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public class Fibonacci {

    private
static Map<Long,Long> map = new
HashMap<Long,Long>();

    static{

        map.put(0L, 1L);

        map.put(1L, 1L);

    }

    public
static void main(String[] args) {

        long
t = System.currentTimeMillis();

        Fibonacci fi = new
Fibonacci();

        System.out.println(fi.cal(36L,map));

        System.out.println(System.currentTimeMillis() - t);

        System.out.println();

        t = System.currentTimeMillis();

        fi = new
Fibonacci();

        System.out.println(fi.cal(36L));

        System.out.println(System.currentTimeMillis() - t);

    }

    public
Long cal(Long n, Map<Long,Long> map){

        if(map.get(n) != null){

            return
map.get(n);

        }else{

            long
i = cal(n-1,map) + cal(n-2,map);

            map.put(n, i);

            return
i;

        }

    }