Introduction

In this blog post, we will explore how to solve the LeetCode problem "371" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

Given two integers a and b, return the sum of the two integers without using the operators + and -. Example 1: Input: a = 1, b = 2 Output: 3 Example 2: Input: a = 2, b = 3 Output: 5 Constraints: -1000 <= a, b <= 1000

Explanation

Here's the solution to add two integers without using the + or - operators:

• Bitwise Operations: The core idea is to simulate addition using bitwise operations. & (AND) finds the carry bits, ^ (XOR) finds the sum bits (without carry), and left shift (<<) moves the carry bits to the next position.

• Iteration: The process is repeated until there are no more carry bits to add.

• Handling Negative Numbers: The code handles negative numbers using the concept of two's complement. A mask is used to ensure the result stays within the 32-bit integer range to mimic the behavior of standard integer addition in many programming environments.

• Runtime & Storage Complexity: O(1) - The number of iterations depends on the number of carry bits, which is bounded by the size of the integers. The space complexity is O(1) as it uses a fixed number of variables.

Code

    def getSum(a: int, b: int) -> int:
    """
    Calculates the sum of two integers without using the + or - operators.
    """
    mask = 0xFFFFFFFF  # Mask for 32-bit integers

    while (b & mask) > 0:
        carry = (a & b) << 1
        a = a ^ b
        b = carry

    return (a & mask) if b > 0 else a