150 Evaluate Reverse Polish Notation

150 Evaluate Reverse Polish Notation. Reverse Polish Notation (RPN) is a mathematical notation in which every operator follows all of its operands. It is also known as postfix notation. To evaluate RPN expressions, a stack can be used. Here's a simple Java code example that demonstrates how to use a stack to calculate the value of an RPN expression: In this example, the evalRPN method takes an array of strings representing the RPN expression. It iterates through each token, and if the token is an operator, it pops two operands from the stack, applies the operation, and pushes the result back onto the stack. If the token is a number, it is simply pushed onto the stack. At the end of the iteration, the stack should contain only one element, which is the result of the RPN expression. The isOperator method checks if a token is an operator, and the applyOperation method applies the corresponding operation to the two operands.