大数开方(Java版)

题目：大数开方

 

Java代码：适合被开方数不超过1000位的。

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

public class Main
{
       public static void main(String[] args) 
       {
               Scanner cin=new Scanner(system.in);
               int t=cin.nextInt();
               BigInteger remain=BigInteger.ZERO;
               BigInteger odd=BigInteger.ZERO;
               BigInteger ans=BigInteger.ZERO;
               for(int i=0;i<t;i++)
               {
                      String s=cin.next();
                      remain=BigInteger.ZERO;
                      odd=BigInteger.ZERO;
                      ans=BigInteger.ZERO;
                      int group=0,k=0;
                      if(s.length()%2==1)
                      {
                              group=s.charat(0)-'0';
                              k=-1;
                      }
                      else
                      {
                              group=(s.charat(0)-'0')*10+s.charat(1)-'0';
                              k=0;
                      }
                      for(int j=0;j<(s.length()+1)/2;j++)
                      {
                              if(j!=0)
                              group=(s.charat(j*2+k)-'0')*10+s.charat(j*2+k+1)-'0';
                              odd=BigInteger.valueOf(20).multiply(ans).add(BigInteger.ONE);
                              remain=BigInteger.valueOf(100).multiply(remain).add(BigInteger.valueOf(group));
                              int count=0;
                              while(remain.compareto(odd)>=0)
                              {
                                     count++;
                                     remain=remain.subtract(odd);
                                     odd=odd.add(BigInteger.valueOf(2));
                              }
                              ans=ans.multiply(BigInteger.TEN).add(BigInteger.valueOf(count));
                      }
                      System.out.println(ans);
                      if(i!=t-1)   System.out.println();
              }
      }
}