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POJ 1001: Exponentiation

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

class Main {
    public static void main(String[] args) {
        Scanner cin=new Scanner(System.in);
        while(cin.hasNext()){
            BigDecimal r=cin.nextBigDecimal();
            int n=cin.nextInt();
            BigDecimal ans= r.pow(n);
            ans=ans.stripTrailingZeros();
            String astring=ans.toPlainString();
            if(astring.startsWith("0."))astring=astring.substring(1);
            System.out.println(astring);
        }
    }
}
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POJ 1001: Exponentiation