Java大数用法参考：https://www.cnblogs.com/jin-nuo/p/5313205.html
1005 大数加法：
import java.util.*; import java.io.*; import java.math.*; public class Main{ public static void main(String[] args) { Scanner cin=new Scanner(System.in); BigInteger a=cin.nextBigInteger(); BigInteger b=cin.nextBigInteger(); System.out.println(a.add(b)); } }
1027 大数乘法：
import java.util.*; import java.io.*; import java.math.*; public class Main{ public static void main(String[] args) { Scanner cin=new Scanner(System.in); BigInteger a=cin.nextBigInteger(); BigInteger b=cin.nextBigInteger(); System.out.println(a.multiply(b)); } }
1029 大数除法 取模：
import java.util.*; import java.io.*; import java.math.*; public class Main{ public static void main(String[] args) { Scanner cin=new Scanner(System.in); BigInteger a=cin.nextBigInteger(); BigInteger b=cin.nextBigInteger(); System.out.println(a.divide(b)); System.out.println(a.remainder(b)); } }