Run-Length Encoding and Decoding II

Parsing and comparing compressed-string representations in Python

This medium-difficulty coding problem tests your ability to parse a custom string format with nested structure, extract semantic content, and compare two superficially different inputs for logical equivalence. It is representative of problems that probe careful parsing and data-structure design.

The core challenge is building a parser that correctly handles multi-digit counts, parenthetical grouping with multipliers, and nesting. Once you can reliably extract the character frequencies from each compressed string, comparison becomes straightforward. Strong solutions parse cleanly (often using a stack or recursive descent), avoid off-by-one errors in count accumulation, and handle edge cases like implicit counts and nested bracket multipliers without duplication or loss.

• Recursive descent parsing and stack-based evaluation
• Extracting and accumulating character frequencies from structured input
• Handling implicit counts and multiplicative effects of nested groups
• Dictionary or counter-based comparison for equivalence