HDU 1316 How Many Fibs?

Vontroy — Sat, 02 Oct 2010 06:00:00 GMT

比较水的大数。。。
代码：

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

public class Main{
    public static void main( String args[] )
    {
        Scanner in = new Scanner( System.in );
        int cnt = 0;
        BigInteger fib1, fib2;
        BigInteger fla1, fla2;
        while( in.hasNext() )
        {
            fib1 = BigInteger.valueOf(1);
            fib2 = BigInteger.valueOf(2);

            fla1 = in.nextBigInteger();
            fla2 = in.nextBigInteger();
            if( fla1.equals(BigInteger.valueOf(0)) && fla2.equals(BigInteger.valueOf(0))) break;

            cnt = 0;

            while( true )
            {
                if( fib1.compareTo(fla1) >= 0 && fib1.compareTo(fla2) <= 0 ) cnt++;
                if( fib2.compareTo(fla1) >= 0 && fib2.compareTo(fla2) <= 0 ) cnt++;
                if( fib1.compareTo(fla2) > 0 || fib2.compareTo(fla2) > 0 ) break;
                fib1 = fib1.add(fib2);
                fib2 = fib2.add(fib1);
            }
            System.out.println( cnt );
        }
    }
}

Vontroy 2010-10-02 14:00 发表评论

POJ 1001 Exponentiation

Vontroy — Tue, 25 May 2010 23:30:00 GMT

Exponentiation

Time Limit: 500MS		Memory Limit: 10000K
Total Submissions: 68964		Accepted: 16146

Description

Problems involving the computation of exact values of very large magnitude and precision are common. For example, the computation of the national debt is a taxing experience for many computer systems.

This problem requires that you write a program to compute the exact value of Rⁿ where R is a real number ( 0.0 < R < 99.999 ) and n is an integer such that 0 < n <= 25.

Input

The input will consist of a set of pairs of values for R and n. The R value will occupy columns 1 through 6, and the n value will be in columns 8 and 9.

Output

The output will consist of one line for each line of input giving the exact value of R^n. Leading zeros should be suppressed in the output. Insignificant trailing zeros must not be printed. Don't print the decimal point if the result is an integer.

Sample Input

Sample Output

548815620517731830194541.899025343415715973535967221869852721
.00000005148554641076956121994511276767154838481760200726351203835429763013462401
43992025569.928573701266488041146654993318703707511666295476720493953024
29448126.764121021618164430206909037173276672
90429072743629540498.107596019456651774561044010001
1.126825030131969720661201

虽然效率低点儿，但代码非常简单，容易实现，真正比赛还是很好用的。。。
import java.io.*;
import java.util.*;
import java.math.*;

public class Main{
    public static void main( String args[] )
    {
        BigDecimal num;
        int n;
        String r;
        Scanner cin = new Scanner(System.in);
        
        while(cin.hasNextBigDecimal())
        {
            num = cin.nextBigDecimal();
            n = cin.nextInt();
            
            num = num.pow(n);
            r = num.stripTrailingZeros().toPlainString();//BigDecimal.toPlainString 避免输出时产生科学计数法形式
            if(r.startsWith("0."))
                r = r.substring(1);
            System.out.println(r);
        }
    }
}

Vontroy 2010-05-26 07:30 发表评论

C++博客-Vontroy-随笔分类-大数/高精度

HDU 1316 How Many Fibs?

POJ 1001 Exponentiation