HDUOJ - 1316 How Many Fibs?

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



[align=left]Problem Description[/align]
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].

[align=left]Input[/align]
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.

[align=left]Output[/align]
For each test case output on a single line the number of Fibonacci numbers fi with a <= fi <= b.

[align=left]Sample Input[/align]

10 100
1234567890 9876543210
0 0

[align=left]Sample Output[/align]

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);
}

}

}