Evaluate Reverse Polish Notation: coding question

Problem

You get an array of strings tokens. The tokens make an arithmetic expression in Reverse Polish Notation (RPN). In RPN, each operator comes after its two operands.

An operand is a value that an operator uses. It can be an integer token or the result of an earlier operation. For example, the tokens ["3", "4", "2", "-", "*"] mean 3 * (4 - 2).

Each token is an integer or one of the operators +, -, * and /. The division of two integers rounds toward zero.

Return the value of the expression as an integer. The input is always a valid expression. It never divides by zero, and all the results fit in a 32-bit integer.

Example 1

Input:: tokens = ["7","3","-","5","*"]
Output:: 20
Explanation:: The expression is (7 - 3) * 5, which is 20.

Example 2

Input:: tokens = ["-7","2","/"]
Output:: -3
Explanation:: The exact value of -7 / 2 is -3.5. The division rounds toward zero, so the result is -3.

Example 3

Input:: tokens = ["6","2","8","3","-","*","+"]
Output:: 16

Constraints

1 <= tokens.length <= 10^4
tokens[i] is an operator (+, -, * or /) or an integer in the range [-200, 200].

SysRound wrote this statement. A reference solution checks every example.

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Leetcode 150. Evaluate Reverse Polish Notation
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Evaluate Reverse Polish Notation
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Citadel
Evaluate Reverse Polish Notation
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Citadel
Evaluate Reverse Polish Notation

Problem

You get an array of strings tokens. The tokens make an arithmetic expression in Reverse Polish Notation (RPN). In RPN, each operator comes after its two operands.

An operand is a value that an operator uses. It can be an integer token or the result of an earlier operation. For example, the tokens ["3", "4", "2", "-", "*"] mean 3 * (4 - 2).

Each token is an integer or one of the operators +, -, * and /. The division of two integers rounds toward zero.

Return the value of the expression as an integer. The input is always a valid expression. It never divides by zero, and all the results fit in a 32-bit integer.

Example 1

Input:: tokens = ["7","3","-","5","*"]
Output:: 20
Explanation:: The expression is (7 - 3) * 5, which is 20.

Example 2

Input:: tokens = ["-7","2","/"]
Output:: -3
Explanation:: The exact value of -7 / 2 is -3.5. The division rounds toward zero, so the result is -3.

Example 3

Input:: tokens = ["6","2","8","3","-","*","+"]
Output:: 16

Constraints

1 <= tokens.length <= 10^4
tokens[i] is an operator (+, -, * or /) or an integer in the range [-200, 200].

SysRound wrote this statement. A reference solution checks every example.

Evaluate Reverse Polish Notation

Problem

Example 1

Example 2

Example 3

Constraints

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Evaluate Reverse Polish Notation

Problem

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