说明：  多数程序设计语言处理整数的能力时有限的，如C语言中，int类型数据范围是-32768－32767。实际问题的处理过程中往往涉及大整数的运算，如RSA加密算法要求至少64bit的整数，设计算法实现大整数的加减运算。
(majority programming language processing integral to the limited capacity, such as C language, int data type is the scope-32768-32767. Practical problems of the treatment process often involves large integer arithmetic, such as the RSA encryption algorithm requires at least 64-bit integers, design algorithm large integer addition and subtraction operations.)