Evaluate Reverse Polish Notation 🧠💻

Problem Description 📝

You are given an array of strings tokens that represents an arithmetic expression in a Reverse Polish Notation. Evaluate the expression and return an integer that represents the value of the expression.

Note that:

• The valid operators are '+', '-', '*', and '/'.

• Each operand may be an integer or another expression.

• The division between two integers always truncates toward zero.

• There will not be any division by zero.

• The input represents a valid arithmetic expression in a reverse polish notation.

• The answer and all the intermediate calculations can be represented in a 32-bit integer.

Examples 🔍

Example 1:

Input: tokens = ["2","1","+","3","*"]
Output: 9
Explanation: ((2 + 1) * 3) = 9

Example 2:

Input: tokens = ["4","13","5","/","+"]
Output: 6
Explanation: (4 + (13 / 5)) = 6

Example 3:

Input: tokens = ["10","6","9","3","+","-11","*","/","*","17","+","5","+"]
Output: 22
Explanation: ((10 * (6 / ((9 + 3) * -11))) + 17) + 5
= ((10 * (6 / (12 * -11))) + 17) + 5
= ((10 * (6 / -132)) + 17) + 5
= ((10 * 0) + 17) + 5
= (0 + 17) + 5
= 17 + 5
= 22

Constraints 🔧

• 1 <= tokens.length <= 10^4

• tokens[i] is either an operator: '+', '-', '*', or '/', or an integer in the range [-200, 200].