hdu--1316--How Many Fibs?(java大数)

How Many Fibs?

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 6371    Accepted Submission(s): 2517

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.util.Scanner;
import java.math.*;

/**
 * @author 日天大帝
 * 第480个斐波数是101位，打个表开480够用
 */
public class Main {
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        final int MAX = 480;
        BigInteger arr[] = new BigInteger[MAX];
        arr[0] = BigInteger.ONE;
        arr[1] = BigInteger.valueOf(2);
        for(int i=2; i<MAX ; ++i){
            arr[i] = arr[i-1].add(arr[i-2]);
        }
        while(cin.hasNext()){
            BigInteger a = cin.nextBigInteger();
            BigInteger b = cin.nextBigInteger();
            if(a.compareTo(b) == 0 && a.compareTo(BigInteger.ZERO) == 0)break;
            int ct = 0;
            for(int i=0;; ++i){
                if(arr[i].compareTo(b) > 0)break;
                if(arr[i].compareTo(a) >= 0)ct++;
            }
            System.out.println(ct);
        } 
    }
}