## Problem You are given a run-length encoded string in the format `" "` repeating (e.g. `"3a2b1c"` -> `"aaabbc"`). Implement a decoder. Additionally implement the encoder: given a plain string, produce its run-length encoding. ```python def decode(s: str) -> str: # "3a2b4c" -> "aaabbcccc" pass def encode(s: str) -> str: # "aaabbc" -> "3a2b1c" pass ``` **Example:** ``` decode("3a2b1c") -> "aaabbc" decode("1a1b1c") -> "abc" encode("aaabbc") -> "3a2b1c" encode("abcd") -> "1a1b1c1d" ``` **Edge cases:** - Count can be multi-digit: `"12a"` -> twelve `a`'s. - Empty string input returns empty string. ## Follow-ups 1. How do you handle malformed input (non-digit before char, count of 0)? 2. When does run-length encoding actually make a string larger? Give a precise condition. 3. How would you extend this to encode/decode binary data (not just ASCII)? 4. How would you implement an in-place encoder without allocating a new string?

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Expansion: Expand a Compressed Run-Length Encoded String

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Problem You are given a run-length encoded string in the format "<count><char>" repeating (e.g. "3a2b1c" -> "aaabbc"). Implement a decoder. Additionally implement the encoder: given a plain string, produce its run-length encoding. Example: Edge cases…

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