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Stack•Pattern: Stack Simulation•Medium

Evaluate Reverse Polish Notation (RPN)

Problem Intuition & Objective

Compute the value of an arithmetic expression in postfix notation.

Time ComplexityO(n)
Optimal
Space ComplexityO(n)
Memory Bounds
Optimal Algorithmic Approach

Stack-based evaluation: linear scan, O(n).

Core Invariants & Edge Cases

  • Push numbers onto the stack
  • On an operator, pop two operands, apply the operator, push result
  • Handle integer division that truncates toward zero
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