UVA 10183 How Many Fibs?

UVA_10183

    根据通项公式粗略计算一下，我们可以知道10^100内的斐波那契数不会超过600个，因此只需要预处理出这些斐波那契数并扫描一遍即可知道在指定范围内的个数。

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

public class Main {
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        BigInteger[] f = new BigInteger[600];
        f[0] = new BigInteger("1");
        f[1] = new BigInteger("2");
        for(int i = 2; i < 600; i ++)
            f[i] = f[i - 1].add(f[i - 2]);
        for(;;)
        {
            BigInteger a, b;
            int res = 0;
            a = cin.nextBigInteger();
            b = cin.nextBigInteger();
            if(a.compareTo(BigInteger.ZERO) == 0 && b.compareTo(BigInteger.ZERO) == 0)
                break;
            for(int i = 0; i < 600; i ++)
                if(f[i].compareTo(a) != -1 && f[i].compareTo(b) != 1)
                    res ++;
            System.out.println(res);
        }
    }
}