HDU1316 How Many Fibs? 【大数】

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

public class Main{
static final int max = 500;
static BigInteger[] arr = new BigInteger[max];
public static void main(String[] args){
Scanner cin = new Scanner(System.in);
BigInteger a, b;
int i, l, r;
arr[1] = BigInteger.ONE; arr[2] = BigInteger.valueOf(2);
for(i = 3; i != max; ++i)
arr[i] = arr[i - 1].add(arr[i - 2]);
while(true){
a = cin.nextBigInteger();
b = cin.nextBigInteger();
if(a.compareTo(BigInteger.ZERO) == 0
&& b.compareTo(BigInteger.ZERO) == 0) break;
l = binarySearch1(a);
r = binarySearch2(b);
System.out.println(r - l);
}
}

public static int binarySearch1(BigInteger n){
int i;
for(i = 1; i < max; ++i)
if(arr[i].compareTo(n) >= 0) return i;
return 0;
}

public static int binarySearch2(BigInteger n){
int i;
for(i = 1; i < max; ++i)
if(arr[i].compareTo(n) > 0) return i;
return 0;
}
}