How many Fibs?【sudt 2321】【大数的加法及其比较】

How many Fibs?

Time Limit: 1000ms   Memory limit: 65536K  有疑问？点这里^_^

题目描述

Recall the definition of the Fibonacci numbers:

f ₁  := 1  
f ₂  := 2  
f _n  :=   f _n-1  +   f _n-2      (n>=3)

Given two numbers a and b, calculate how many Fibonacci numbers are in the range [a,b].

输入

The input contains several test cases. Each test case consists of two non-negative integer numbers a and b. Input is terminated by a=b=0. Otherwise, a<=b<=10¹⁰⁰. The numbers aand b are given with no superfluous leading zeros.

输出

 

示例输入

10 100

1234567890 9876543210

0 0

示例输出

5

4

提示

 

来源

2000/2001 University of Ulm Local Contest

示例程序

题目大意：

输入两个整数，求这两个整数之间的斐波纳契数的个数，即求[a,b]之间斐波那契数的个数，输入以0 0结束（a,b两个数可以到10^100次幂）

代码：

很多大数的问题用java做的话一定比c语言或者c++语言做起来简单~

 1 import java.io.*;

 2 import java.math.*;

 3 import java.util.*;

 4 public class Main

 5 {

 6     public static void main(String args[])

 7     {

 8         Scanner scn=new Scanner(System.in);

 9         while(true)

10         {

11             BigInteger a=scn.nextBigInteger();

12             BigInteger b=scn.nextBigInteger();

13             if(a.equals(new BigInteger("0"))&&b.equals(new BigInteger("0")))

14             {

15                 break;

16             }

17             BigInteger f[]=new BigInteger[20000];

18             f[1]=new BigInteger("1");

19             f[2]=new BigInteger("2");

20             int i;

21             for(i=3;i<=600;i++)

22             {

23                 int temp=i;

24                 f[i]=f[temp-1].add(f[temp-2]);

25             }

26             int count=0;

27             for(i=1;i<=600;i++)

28             {

29                 if(f[i].compareTo(a)==0)

30                 {

31                     count=1;

32                 }

33                 else if(f[i].compareTo(a)>0&&f[i].compareTo(b)<=0)

34                 {

35                     count++;

36                 }

37                 else if(f[i].compareTo(b)>0)

38                 {

39                     break;

40                 }

41             }

42             System.out.println(count);

43         }

44     }

45 } 

View Code