Given a list of strings representing an arithmetic expression in Reverse Polish Notation (RPN), evaluate the expression and return its integer value. The valid operators are +, -, *, and /. Division between two integers truncates toward zero. The input is guaranteed to be a valid RPN expression, and there is no division by zero. All calculations and the result fit in a 32-bit signed integer.
Example 1
Input: [5,3,+,8,*]
Output: 64
Explanation: ((5 + 3) * 8) = 64
Example 2
Input: [7,2,/,4,-]
Output: -1
Explanation: ((7 / 2) - 4) = (3 - 4) = -1
Example 3
Input: [-3,-2,*,6,+]
Output: 12
Explanation: ((-3 * -2) + 6) = (6 + 6) = 12
Constraints
Case 1
Input: ['1','2','+','4','*']
Expected: 12
Case 2
Input: ['9','3','/','2','-']
Expected: 1
Case 3
Input: ['10','-5','+','2','*']
Expected: 10
Case 4
Input: ['100','200','+','50','/']
Expected: 6
Case 5
Input: ['-10','2','/','3','+']
Expected: -2