Evaluate Reverse Polish Notation
Description: Evaluate an arithmetic expression in Reverse Polish Notation. Valid operators are +, -, *, /. Division truncates toward zero.
Example 1:
Input: tokens = ["2","1","+","3","*"]
Output: 9
Example 2:
Input: tokens = ["4","13","5","/","+"]
Output: 6
Constraints:
1 <= tokens.length <= 10⁴
Деление на ноль не встречается
Recommended time and space complexity
O(n) time and O(n) space.
Hint 1
In postfix notation operands come before the operator. Which structure gives you the last two values?
Hint 2
Stack: push numbers, on an operator pop two and push the result.
Hint 3
Order matters: the first popped value is the right operand.