Sum of Two Integers

Question

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.

Tags

• Bit Manipulation

Thought

Reference: http://bookshadow.com/weblog/2016/06/30/leetcode-sum-of-two-integers/

Code

class Solution(object):
    def getSum(self, a, b):
        """
        :type a: int
        :type b: int
        :rtype: int
        """
        MAX_INT = 0x7FFFFFFF
        MASK = 0x100000000
        while b:
            a, b = (a ^ b) % MASK, ((a & b) << 1) % MASK
        return a if a <= MAX_INT else ~((a & MAX_INT) ^ MAX_INT)