11 lines
567 B
Python
11 lines
567 B
Python
def decode_cyclic(s: str):
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"""
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takes as input string encoded with encode_cyclic function. Returns decoded string.
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"""
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# split string to groups. Each of length 3.
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groups = [s[(3 * i):min((3 * i + 3), len(s))] for i in range((len(s) + 2) // 3)]
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# reverse the cycle operation: shift the last character to the front
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# encode does: abc -> bca (shift left)
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# decode should: bca -> abc (shift right, i.e., last char to front)
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groups = [(group[-1] + group[:-1]) if len(group) == 3 else group for group in groups]
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return "".join(groups) |