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Stack or Pointer Expression Evaluation
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Stack or Pointer Expression Evaluation

MediumPython

Problem

Betterworks goal configurations may contain arithmetic expressions that combine numeric targets, operators, and parentheses. Implement an evaluator that computes the integer result without using Python's eval or another expression-evaluation library.

Formal Specification

Implement evaluate_expression(expression), where expression is a valid string containing non-negative integer operands, the binary operators +, -, *, and /, parentheses, and optional spaces. Return the expression's integer value. Multiplication and division have higher precedence than addition and subtraction. Parentheses override normal precedence. Division must truncate toward zero.

You may use a stack-based approach or equivalent pointer-based parsing logic. Inputs contain no unary operators, and division by zero does not occur.

Constraints

  • 1 <= len(expression) <= 10^5
  • Each operand is an integer from 0 through 10^9
  • The expression is syntactically valid
  • Parentheses are balanced
  • Division by zero does not occur

Function Signature

def evaluate_expression(expression):
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