UVa 495 - Fibonacci Freeze

　　题目大意：计算斐波那契数列的第n项。

　　由于结果会很大，要用到大数。开始本来想节省空间的，就没用数组保存，结果超时了...

 import java.io.*;
 import java.util.*;
 import java.math.*;

 class Main
 {
     public static void main(String args[])
     {
         Scanner sc = new Scanner(System.in);
         BigInteger[] F = new BigInteger[5010];
         F[0] = BigInteger.valueOf(0);
         F[1] = BigInteger.valueOf(1);
         for (int i = 2; i <= 5000; i++)
             F[i] = F[i-1].add(F[i-2]);
         int n;
         while (sc.hasNext())
         {
             n = sc.nextInt();
             System.out.println("The Fibonacci number for " + n +" is " + F[n]);
         }
     }
 }