HDUOJ

How Many Fibs?

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 4592    Accepted Submission(s): 1803

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.io.*;
import java.math.*;
import java.text.*;
import java.util.*;

public class Main {

	public static void main(String[] args) {
		Scanner cin = new Scanner(System.in); 
		BigInteger []Fib = new BigInteger[1024];
		Fib[0] = Fib[1] = BigInteger.valueOf(1); 
		for(int i = 2; i < 1024; i++)
			Fib[i] = Fib[i-1].add(Fib[i-2]);
		while(cin.hasNextBigInteger()){
			BigInteger l = cin.nextBigInteger();
			BigInteger r = cin.nextBigInteger();
			int cnt = 0;
			if(l.compareTo(BigInteger.ZERO)==0 && r.compareTo(BigInteger.ZERO)==0)
				return ;
			if(l.compareTo(r) > 0){
				BigInteger t = l;
				l = r;
				r = t;
			}
			for(int i = 1; i < 1024; i++)
				if(Fib[i].compareTo(l)>=0 && Fib[i].compareTo(r)<=0)
					cnt++;
			System.out.println(cnt);
		}
			
	}

}