How many Fibs?（JAVA）大数

Problem B: How many Fibs?

Recall the definition of the Fibonacci numbers:

f₁ := 1 
f₂ := 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].

Input Specification

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 a and b are given with no superfluous leading zeros.

Output Specification

For each test case output on a single line the number of Fibonacci numbers f_i with a<=f_i<=b.

Sample Input

10 1001234567890 98765432100 0

Sample Output

54

题目看完，显然是高精度，C肯定可以做，不过这里给出JAVA代码。

import java.math.*;  
import java.util.*;  
import java.io.*;   
public class Main{  
    public static void main(String[] args) {  
        Scanner cin = new Scanner(System.in); 
        BigInteger [] s=new BigInteger [50010];
        BigInteger n,m;
        BigInteger k=new BigInteger("0");
        s[2]=new BigInteger ("2");
        s[1]=new BigInteger ("1");
        for(int i=3;i<=50000;i++)
        {
        s[i]=s[i-1].add(s[i-2]);
        }
        while(cin.hasNextBigInteger()){  
        int sum=0;
        n=cin.nextBigInteger();
        m=cin.nextBigInteger();
        if(n.compareTo(k)==0&&m.compareTo(k)==0)
        break;
        for(int i=1;i<=50000;i++)
        {
        if((s[i].compareTo(n)>=0)&&(s[i].compareTo(m)<=0))
        sum++;
        }
        System.out.println(sum);  
        }  
    }  

}

唯一需要注意的是数组大小，开到10W会超时,1W会WA，大概估算开到5W就可以了。