hdu 1316 How Many Fibs?【JAVA大数】

How Many Fibs?

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 2814    Accepted Submission(s): 1112

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]. 

 

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

 

Source

University of Ulm Local Contest 2000

 

Recommend

Eddy

 

又钻了 JAVA 的空子，一下就 AC 了，

但是奇怪的是，为什么我把内存减少一半，空间没有节省多少，时间反而多了一些

8276754	2013-05-10 16:30:33	Accepted	1316	171MS	3704K	955 B	Java	free斩
8276732	2013-05-10 16:28:32	Accepted	1316	140MS	3752K	958 B	Java	free斩

import java.util.*;
import java.math.*;
import java.io.*;

public class Main {
	public static void main(String args[]) {
		BigInteger []f = new BigInteger[500];
		f[1] = new BigInteger("1");
		f[2] = new BigInteger("2");
		for(int i = 3; i < 500; i++) {
			f[i] = f[i-1].add(f[i-2]);
		}
		/* 
		String s = f[499].toString(); //算出有 105 位
		int len = s.length();
		System.out.println(len);
		*/
		Scanner cin = new Scanner(new BufferedInputStream(System.in));
		BigInteger a,b;
		BigInteger c = BigInteger.valueOf(0);
		while(cin.hasNextBigInteger()) {
			a = cin.nextBigInteger();
			b = cin.nextBigInteger();
			
			if(a.compareTo(BigInteger.valueOf(0)) == 0 && b.compareTo(c) == 0) {
				break;
			}
			
			int ans = 0;
			for(int i = 1; i < 500; i++) {
				if(f[i].compareTo(b) == 1) {
					break;
				}
				if(f[i].compareTo(a) >= 0 && f[i].compareTo(b) <= 0) {
					ans++;
				}
			}
			System.out.println(ans);
		}
	}
}