fix: operator precedence for leetcode 227 [basic calculator ii]

[Gumparthypavankumar]

1. What is now different from before?

The implementation now reverses the numbers and operators stacks before applying + and - operators.This ensures that + and - are evaluated in left-to-right order, which matches the expected behavior of the expression (i.e., left-associative evaluation). Previously, operators were applied in reverse order, leading to incorrect results like 1-1+1 → -1 instead of 1.

2. What is the reason for the change?

• and - are left-associative operators with the same precedence, and must be processed in the order they appear.

3. Anything to watch out for?

Space complexity increases slightly due to the temporary numRev and opRev stacks, but remains O(n).