UVa 748/POJ 1001 exponentiation: Application of power & regular expression of floating-point high precision

748-exponentiation

Time limit:3.000 seconds

Http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=97&page=show_problem &problem=689

http://poj.org/problem?id=1001

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

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

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

Output
The output would consist of one for each line of input giving the exact value of Rn leading zeros and insignificant t Railing zeros should is suppressed in the output.

Sample Input

95.123 12
0.4321 20
5.1234 15
6.7592 9
98.999 10
1.0100 12

Sample Output

548815620517731830194541.899025343415715973535967221869852721
.00000005148554641076956121994511276767154838481760200726351203835429763013462401
43992025569.928573701266488041146654993318703707511666295476720493953024
29448126.764121021618164430206909037173276672
90429072743629540498.107596019456651774561044010001
1.126825030131969720661201

Description
It is a very common problem to perform high precision calculation on the number of large numbers and high precision. For example, the calculation of national debt is a problem of this sort.

Now the problem for you to solve is: for a real R (0.0 < R < 99.999), a write program is required to accurately compute the n-th (Rn) of R, where n is an integer and 0 < n <= 25.

Input
The T input includes multiple sets of R and N. The values for R are in columns 1th through 6th, and N is in the 8th and 9th columns.

Output
For each set of inputs, the output line is required, which contains the exact n-th side of R. The output needs to get rid of the leading 0 not 0. If the output is an integer, do not output a decimal point.

Complete code:

/*uva:0.242s*/
/*poj:125ms,3340kb*/
    
import java.util.*;  
Import java.math.*;  
Import java.io.*;  
    
public class Main {  
    static Scanner cin = new Scanner (new Bufferedinputstream (system.in));  
    
    public static void Main (string[] args {while  
        (Cin.hasnext ()) {  
            BigDecimal R = Cin.nextbigdecimal ();  
            int n = cin.nextint ();  
            String str = R.POW (n). Striptrailingzeros (). toplainstring ();  
            Returns the string representation of this bigdecimal that removes all trailing zeros, without referring to the number segment  
            if (Str.indexof ("0") < Str.indexof ("."  
                )) str = Str.replacefirst ("^0*", "");  
                ^ matches the start of a string, * means repeat 0 or more times  
            System.out.println (str);}}  

See more highlights of this column: http://www.bianceng.cnhttp://www.bianceng.cn/Programming/sjjg/