【JAVA大数训练】How Many Fibs?

How Many Fibs?

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 3628    Accepted Submission(s): 1457

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

Output

For each test case output on a single line the number of Fibonacci numbers fi with a

Sample Input

10 100
1234567890 9876543210
0 0

Sample Output

5
4

Source

​​University of Ulm Local Contest 2000​​

import java.math.BigInteger;
import java.util.Scanner;
public class Main {
  public static void main(String[] args) {
    Scanner input=new Scanner(System.in);
    BigInteger [] p=new BigInteger[10010];
        p[1]=BigInteger.valueOf(1);p[2]=BigInteger.valueOf(2);
    for (int i = 3; i      p[i]=p[i-1].add(p[i-2]);
    }
    while(input.hasNext())
    {
      BigInteger n=input.nextBigInteger();
      BigInteger m=input.nextBigInteger();
      int sum=0;
      if(n.compareTo(BigInteger.ZERO)==0&&m.compareTo(BigInteger.ZERO)==0)
      break;
      for (int i = 1; i         if(p[i].compareTo(n)>=0&&p[i].compareTo(m)          sum++;
      }
        System.out.println(sum);
    }
  }
}

总结

BigIngter a与BigIngter b比大小

如果a比b大

a.compareTo(b)>0

如果a比b小

a.compareTo(b)

如果a等于b

a.compareTo(b)==0

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