Sum of Two Integers

Problem Link

Approach

Add a and b without using + or -.

Use bitwise operations:

• carry = (a & b) << 1
• a = a ^ b (sum without carry)
• Repeat until carry is 0

Python integers are unbounded, so mask to 32 bits and handle sign extension for negative results.

Time Complexity: O(1) bounded word size
Space Complexity: O(1)

Code

class Solution:
    def getSum(self, a: int, b: int) -> int:
        mask = 0xFFFFFFFF

        while b:
            carry = (a & b) << 1
            a = (a ^ b) & mask
            b = carry & mask

        return a if a <= 0x7FFFFFFF else ~(a ^ mask)