Java 大数之大数高精度斐波那契 UVA_10579&&HDU1316 How many Fibs?

UVA_10579

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

public class UVA_10579 {//fibs[20] = 6765 ,fibs的上限达到上千位 

    public static void main(String[] args) {  
        Scanner cin = new Scanner(System.in);  

        BigInteger[] fibs = new BigInteger[2000];  

        fibs[1] = new BigInteger("1");  
        fibs[2] = new BigInteger("1");  

        int i;  
        for(i = 3 ; i < 2000 ; ++i){  
            fibs[i] = fibs[i-1].add(fibs[i-2]);  
        }  

        while(cin.hasNext()){  
            int n = cin.nextInt();  

            System.out.println(fibs[n]);  
        }  
    }  

} 

HDU1316

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

public class Main {  
    public static void main(String []args)throws Exception{  
        Scanner in = new Scanner(System.in);  
        while(in.hasNext()){  
        String a=in.next();  
        String b=in.next();  
        if(a.equals("0")&&b.equals("0"))  
            break;  
        BigInteger c = new BigInteger(a);  
        BigInteger d = new BigInteger(b);  
        int sum=fibo(c,d);  
        System.out.println(sum);  
        }  
        in.close();  
    }  
    public static int fibo(BigInteger a,BigInteger b){  
        int sum =0;  
        BigInteger f = new BigInteger("1");  
        BigInteger s = new BigInteger("2");  
        while(true){  

            if(f.compareTo(b)>0)  //前一个数比后一个数大
                break;  
            if(f.compareTo(a)>=0)  //前一个数比后一个数大或相等
                sum++;  
            BigInteger t = f;  
            f=s;  
            s=s.add(t);  
        }  
        return sum;  
    }  
}  

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