Question
Evaluate an arithmetic expression given in Reverse Polish Notation as a list of string tokens. Valid operators are +, -, *, and /; every other token is an integer (possibly negative). Division truncates toward zero. Return the integer result. The expression is always valid and has 1 to 10^4 tokens; intermediate and final values fit in a signed 32-bit integer.
eval_rpn(tokens: list[str]) → int[["2","1","+","3","*"]]out9State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.
Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.