UVa 495

　　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]);
        }
    }
}