hdoj 1753 (Java)

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();
}
}