Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -.

Example 1:

Input: a = 1, b = 2Output: 3

Example 2:

Input: a = -2, b = 3Output: 1

 

class Solution(object):    def getSum(self, a, b):        """        :type a: int        :type b: int        :rtype: int        """        MAX = 0x7FFFFFFF        #符号位为0的最大值        Mask = 0xFFFFFFFF        #符号位为1的最大值                    while b!=0:            suma=(a^b)&Mask            carry=((a&b)<<1)&Mask            a=suma            b=carry                return a if a<=MAX else ~(a^Mask)#Python 比较麻烦的地方是 要Mask.....