Evaluate Reverse Polish Notation
Evaluate the value of an arithmetic expression in Reverse Polish Notation. Valid operators are +, -, *, and /. Each operand may be an integer or another expression.
Examples of Reverse Polish Notation:
['2', '1', '+', '3', '*']yields(2 + 1) * 3 = 9.['4', '13', '5', '/', '+']yields4 + (13 / 5) = 6.6(evaluated as6in integer division).
Your task is to write a function that takes an array of strings representing the postfix expression and returns the evaluation result of that expression.
[ "2", "1", "+", "3", "*" ]
Explanation. `(2 + 1) * 3 = 9`
[ "4", "13", "5", "/", "+" ]
Explanation. `4 + (13 / 5) = 6` using integer division
[ "10", "6", "9", "3", "+", "-11", "*", "/", "*", "17", "+", "5", "+" ]
Explanation. The expression evaluates step by step as: `10 * (6 / ((9 + 3) * -11)) * 17 + 5 = 22`
Follow-up: Can you improve your solution to handle additional operators like `^` (exponentiation) or `mod`?
- The given tokens are always a valid sequence. - All operations are between two integers. - Division between two numbers truncates towards zero (integer division).
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