python不用加号实现加法

问题:

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.

class Solution(object):def getSum(self, a, b):"""
        :type a: int:type b: int:rtype: int"""
        if(0 == b):return asum1 = a^bcarry = (a&b)<<1return Solution().getSum(sum1,carry)if __name__ == '__main__'：l = Solution().getSum(3,7)print l