Problem B: How many Fibs?
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 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 fi with a<=fi<=b.
Sample Input
10 100 1234567890 9876543210 0 0
Sample Output
5 4
直接利用java大数可以水过
import java.util.*; import java.math.*; public class Main { public static void main(String args[]) { Scanner cin=new Scanner(System.in); BigInteger f[]=new BigInteger[1000]; BigInteger a,b; int i,ans; f[1]=BigInteger.ONE; f[2]=BigInteger.valueOf(2); for(i=3;i<1000;i++) f[i]=f[i-1].add(f[i-2]); while(true) { a=cin.nextBigInteger(); b=cin.nextBigInteger(); if(a.compareTo(b)>0) { System.out.println(0); continue; } if(a.compareTo(BigInteger.ZERO)==0&&b.compareTo(BigInteger.ZERO)==0) break; ans=0; for(i=1;i<1000;i++) { if(f[i].compareTo(a)>=0&&f[i].compareTo(b)<=0) ans=ans+1; } System.out.println(ans); } } }