hdoj 1753 (Java)

1.import java.math.BigDecimal;
import java.util.Scanner;
public class Main {
  public static void main(String[] args) {
    Scanner cin = new Scanner(System.in);
    while (cin.hasNext()) {
      BigDecimal a = cin.nextBigDecimal();
      BigDecimal b = cin.nextBigDecimal();
      a = a.add(b);
      if (a.compareTo(BigDecimal.valueOf(0.0)) == 0) {
        System.out.println(0);
        continue;
      }
      String out = new String(a.toPlainString());
      int l = out.length();
      boolean flag = false;
      for (int i = 0; i < l; i++)
        if (out.charAt(i) == '.')
          flag = true;
      int q = l - 1;
      while (out.charAt(q) == '0')
        q--;
      if (out.charAt(q) == '.')
        q--;
      if (flag == false && out.charAt(q) != '.')
        q = l-1;
      int p = 0;
      while (out.charAt(p) == '0')
        p++;
      if (out.charAt(p) == '.')
        System.out.print(0);
      for (int i = p; i <= q; i++)
        System.out.print(out.charAt(i));
      System.out.println();
    }
    cin.close();
  }
}