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String•Pattern: Length-Prefix Encoding•Medium

Encode and decode strings (no delimiter in charset)

Problem Intuition & Objective

Design encode/decode functions to serialize a list of strings with no guaranteed delimiter.

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

Length-prefix encoding: `len(s) + '#' + s`.

Core Invariants & Edge Cases

  • Prefix each string with its length followed by a fixed separator e.g. '5#hello'
  • Decode reads the length, then reads exactly that many characters
  • This handles any characters including the separator
Previous ProblemLongest palindromic substringNext Problem Minimum window substring containing all chars of T

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