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].
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
分析：求a和b之间的斐波拉契数的个数。
import java.math.BigInteger;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
BigInteger []s = new BigInteger[1000];
s[1] = BigInteger.valueOf(1);
s[2] = BigInteger.valueOf(2);
for(int i = 3; i < 1000; i++) {
s[i] = s[i-1].add(s[i-2]);
}
while(in.hasNextBigInteger()) {
BigInteger a = in.nextBigInteger();
BigInteger b = in.nextBigInteger();
if(a.compareTo(BigInteger.ZERO)==0&&b.compareTo(BigInteger.ZERO)==0) {
break;
}
int cnt = 0;
for(int i = 1; i < 1000; i++) {
if(s[i].compareTo(a)>=0 && s[i].compareTo(b)<=0) {
cnt++;
}
}
System.out.println(cnt);
}
in.close();
}
}