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50545d10c5
* Removed unused commit * Added wikipedia url * Renamed parameter, changed decoding to use list comprehension
49 lines
1.3 KiB
Python
49 lines
1.3 KiB
Python
# https://en.wikipedia.org/wiki/Run-length_encoding
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def run_length_encode(text: str) -> list:
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"""
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Performs Run Length Encoding
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>>> run_length_encode("AAAABBBCCDAA")
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[('A', 4), ('B', 3), ('C', 2), ('D', 1), ('A', 2)]
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>>> run_length_encode("A")
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[('A', 1)]
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>>> run_length_encode("AA")
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[('A', 2)]
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>>> run_length_encode("AAADDDDDDFFFCCCAAVVVV")
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[('A', 3), ('D', 6), ('F', 3), ('C', 3), ('A', 2), ('V', 4)]
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"""
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encoded = []
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count = 1
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for i in range(len(text)):
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if i + 1 < len(text) and text[i] == text[i + 1]:
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count += 1
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else:
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encoded.append((text[i], count))
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count = 1
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return encoded
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def run_length_decode(encoded: list) -> str:
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"""
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Performs Run Length Decoding
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>>> run_length_decode([('A', 4), ('B', 3), ('C', 2), ('D', 1), ('A', 2)])
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'AAAABBBCCDAA'
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>>> run_length_decode([('A', 1)])
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'A'
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>>> run_length_decode([('A', 2)])
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'AA'
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>>> run_length_decode([('A', 3), ('D', 6), ('F', 3), ('C', 3), ('A', 2), ('V', 4)])
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'AAADDDDDDFFFCCCAAVVVV'
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"""
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return "".join(char * length for char, length in encoded)
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if __name__ == "__main__":
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from doctest import testmod
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testmod(name="run_length_encode", verbose=True)
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testmod(name="run_length_decode", verbose=True)
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