How Many Fibs?

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 6345    Accepted Submission(s): 2506


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

Source

​​University of Ulm Local Contest 2000​​


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做了上个大数 没想到两道题的斐波那契数列初始化一个f[2]=1,一个f[2]=2不一样。。坑

import java.math.BigInteger;
import java.util.Scanner;

public class Main {

  public static void main(String[] args) {
    Scanner sca=new Scanner(System.in);
    BigInteger f[]=new BigInteger[1005];
    f[1]=BigInteger.ONE;
    f[2]=new BigInteger("2");
    for(int i=3;i<=1000;i++)
    {
      f[i]=f[i-2].add(f[i-1]);
    }
    while(sca.hasNext())
    {
      BigInteger l=sca.nextBigInteger();
      BigInteger r=sca.nextBigInteger();
      if(l.compareTo(r)==0&&l.compareTo(BigInteger.ZERO)==0) break;
      int sum=0;
      for(int i=1;i<=1000;i++)
      {
        if(f[i].compareTo(r)>0) break;
        if(f[i].compareTo(l)>0&&f[i].compareTo(r)<0){
          sum++;
        }
        if(f[i].compareTo(l)==0||f[i].compareTo(r)==0){
          sum++;
        }
      }
      System.out.println(sum);
    }
  }
}