Calculator with Parentheses

Evaluate a valid integer expression containing non-negative decimal integers, ASCII spaces, binary +, -, *, and /, unary + and -, and balanced parentheses.
Parentheses have the highest grouping priority, multiplication and division have higher precedence than addition and subtraction, and binary operators with the same precedence are evaluated from left to right. Integer division truncates toward zero, and the expression never divides by zero.
Every parsed integer, intermediate value, and final result fits in a signed 32-bit integer. Return the final result.

Function
calculateExpression(expression: String) → int

Examples
Example 1
expression = "1 + (2 - 3) + 4"
return = 4
The parenthesized subexpression evaluates to -1.
Example 2
expression = "-(10 - (3 + 2))"
return = -5
Unary minus applies to the complete parenthesized expression.

Constraints
1 <= expression.length <= 10^5
The expression is valid and parentheses are balanced.
The final result and every parsed integer fit in signed 32-bit range.

The trick is one pass with a stack and a running sign, or recursive descent with three levels: expression, term, factor. The factor level handles unary +/-, integers, and parenthesized groups, so "-(...)" falls out naturally. The stack version keeps a result, a sign, and a current number, pushes both on "(", and pops on ")". Multiplication and division need a last-term trick: keep the pending term and apply * or / to it before adding it to the total. The common pitfall is division. Integer division must truncate toward zero, so in Python don't use // on negatives, use int(a / b) or a manual sign fix. Another pitfall is recursion depth at 10^5 characters with deeply nested parentheses, so prefer an explicit stack. StealthCoder is the hedge if you freeze on the unary or precedence wiring during the live OA.

If you see this problem in your OA tomorrow, the play is to recognize the pattern in 30 seconds. StealthCoder buys you that recognition.