Evaluate an expression whose operators follow their operands, using integer arithmetic with truncation toward zero.
A good solution should
- State the invariant or decision rule that makes the approach correct.
- Explain the time and space complexity in terms of the input sizes and required output.
- Handle empty, minimal, duplicate, and boundary-shaped inputs covered by the contract.
Reasoning prompt
Pop the right operand before the left operand. Division with negative inputs must follow truncation toward zero, not floor division.
Use the linked judge for the canonical problem. The examples above are compact TRT checks; write additional cases before submitting, especially for the boundary that tends to break your chosen invariant.