Code RoomReverse Polish notation evaluator
MediumPrep Room Coding #168

Reverse Polish notation evaluator

CodingAlgorithms & data structuresMid–Senior~25 min

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.

Implement
eval_rpn(tokens: list[str]) → int
Examples
in[["2","1","+","3","*"]]out9
What a strong answer looks like

State 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.

0:00 of about 25 min
InputExpectedGot
[["2","1","+","3","*"]]9not run yetsample