Swap Two Numbers Without Built-in | Dataford Interview Questions

A Manheim vehicle-listing workflow sometimes needs to exchange two integer state values, such as source and destination positions. Implement the swap without using a temporary variable, Python tuple unpacking, or any built-in swap function.

Write a function that accepts two integers and returns them in reversed order. The input values may be positive, negative, or zero, and the function must preserve their exact values.

Formal Specification

Input: Two integers a and b.
Output: A two-element list [b, a], produced without a third variable or tuple unpacking.
Do not use a built-in swap operation.
Do not convert the values to strings or use an auxiliary collection to hold the originals.

You may use arithmetic operations. Python integers have arbitrary precision, so integer overflow does not need to be handled.

Constraints

-10^9 <= a, b <= 10^9
The two inputs may be equal
Do not use a temporary variable
Do not use tuple unpacking or a built-in swap operation
Use O(1) extra space

Function Signature

def swap_numbers(a, b):

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