Evaluate Reverse Polish Notation https://leetcode.com/problems/evaluate-reverse-polish-notation/description/

polishNotation.cs

public class Solution {
    public int EvalRPN(string[] tokens) {
        char[] operators = { '+', '-', '*', '/' };
        Stack<int> operands = new Stack<int>();

        foreach (string token in tokens)
        {
            bool isOperator = token.Length == 1 && token.IndexOfAny(operators) != -1;
            if (!isOperator)
            {
                operands.Push(Convert.ToInt32(token));
            }
            else
            {
                int result = 0;
                int b = operands.Pop();
                int a = operands.Pop();
                switch (token[0]) {
                    case '+': result = a + b; break;
                    case '-': result = a - b; break;
                    case '*': result = a * b; break;
                    case '/': result = a / b; break;
                }

                operands.Push(result);
                Console.WriteLine($"{a} {token} {b} = {result}");
            }
        }

        return operands.Pop();
    }
}