How Many Fibs_hdu_1316(大数).java

How Many Fibs?

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 3098    Accepted Submission(s): 1232

Problem Description

Recall the deFinition of the Fibonacci numbers: 
f1 := 1 
f2 := 2 
fn := fn-1 + fn-2 (n >= 3) 

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

 

Input

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 <= 10^100. The numbers a and b are given with no superfluous leading zeros.

 

Output

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

 

Sample Input

  
  

   
   10 100
1234567890 9876543210
0 0
  
  

 

Sample Output

  
  

   
   5
4
  
  

 

import java.math.BigInteger;
import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner input=new Scanner(system.in);
		BigInteger f[]=new BigInteger[505];
		f[0]=BigInteger.valueOf(1);
		f[1]=BigInteger.valueOf(2);
		for(int i=2;i<502;i++){
			f[i]=f[i-1].add(f[i-2]);
		}
		while(true){
			BigInteger a=input.nextBigInteger();
			BigInteger b=input.nextBigInteger();
			if(a.equals(BigInteger.ZERO)&&b.equals(BigInteger.ZERO))
				break;
			int sum=0;
			for(int i=0;i<502&&b.compareto(f[i])>=0;i++){
				if(f[i].compareto(a)>=0)
					sum++;
			}
			System.out.println(sum);
		}
	}
}