hdu 1250 java大数练习

Problem Description
A Fibonacci sequence is calculated by adding the previous two members the sequence, with the first two members being both 1.
F(1) = 1, F(2) = 1, F(3) = 1,F(4) = 1, F(n>4) = F(n - 1) + F(n-2) + F(n-3) + F(n-4)
Your task is to take a number as input, and print that Fibonacci number.

Input
Each line will contain an integers. Process to end of file.

Output
For each case, output the result in a line.

Sample Input
100

Sample Output
4203968145672990846840663646

Note:
No generated Fibonacci number in excess of 2005 digits will be in the test data, ie. F(20) = 66526 has 5 digits.

题解：

java大数。注意提交的时候把类改为Main，不然每次都出错。

代码：

import java.math.BigInteger;import java.util.Scanner;public class HatsFibonacci {    public static void main(String[] args) {        // TODO Auto-generated method stub        Scanner in = new Scanner(System.in);        BigInteger num[] = new BigInteger[10000];        num[1] = BigInteger.ONE;        num[2] = BigInteger.ONE;        num[3] = BigInteger.ONE;        num[4] = BigInteger.ONE;        while(in.hasNext())        {            int n = in.nextInt();            for(int i=5;i<=n;i++)            {                num[i] = num[i-1].add(num[i-2]).add(num[i-3]).add(num[i-4]);            }            System.out.println(num[n]);        }        }    }