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74 lines
2.1 KiB
Plaintext
74 lines
2.1 KiB
Plaintext
---
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title: '271. Encode and Decode Strings'
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description: Design an algorithm to encode a list of strings to a string. The encoded string is then sent over the network and is decoded back to the original list of strings
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sidebar:
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label: 'Encode and Decode Strings'
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badge: 'Medium'
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---
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<Badge variant="accent">Array</Badge>
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::::warning
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Could you write a generalized algorithm to work on any possible set of characters?
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::::
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### Example 1:
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- Input: `dummy_input = ["Hello","World"]`
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- Output: `["Hello","World"]`
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- Explanation: Machine `1`: Codec encoder = new Codec(); String msg = encoder.encode(strs); Machine `1` ---msg---> Machine `2` Machine `2`: Codec decoder = new Codec(); `String[] strs` = decoder.decode(msg);
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### Example 2:
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- Input: `dummy_input = [""]`
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- Output: `[""]`
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### Constraints:
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- `1 <= strs.length <= 200`
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- `0 <= strs[i].length <= 200`
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- `strs[i]` contains any possible characters out of 256 valid ASCII characters.
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## Approach
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::::warning
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The diagram traces the code below literally. That code does not solve the problem: both `encode` and `decode` have only a docstring for a body, so each returns `None` and `codec.decode(codec.encode(strs))` yields `None` instead of `strs`.
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::::
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```mermaid
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flowchart TD
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subgraph state["state — Codec holds no fields"]
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X["Codec() — nothing is stored between encode and decode"]
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end
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subgraph encode["encode(strs)"]
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E1["docstring only — no statement runs"] --> E2(["return None"])
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end
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subgraph decode["decode(s)"]
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D1["docstring only — no statement runs"] --> D2(["return None"])
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end
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state --> encode
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state --> decode
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```
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## Solution
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```py
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class Codec:
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def encode(self, strs: List[str]) -> str:
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"""Encodes a list of strings to a single string.
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"""
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def decode(self, s: str) -> List[str]:
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"""Decodes a single string to a list of strings.
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"""
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# Your Codec object will be instantiated and called as such:
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# codec = Codec()
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# codec.decode(codec.encode(strs))
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```
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## Explanation
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<YouTube id="B1k_sxOSgv8" title="Encode and Decode Strings - Leetcode 271 - Python" />
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