题目描述：
LeetCode 371. Sum of Two Integers
Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -.
Example:
Given a = 1 and b = 2, return 3.
题目大意：
不使用加减法，计算两个整数a和b的和。
解题思路：
解法I ...
LeetCode 371. Sum of Two Integers
Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -.
Example:
Given a = 1 and b = 2, return 3.
不使用加减法，计算两个整数a和b的和。
解法I ...