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38 lines
793 B
Python
38 lines
793 B
Python
from typing import Tuple, List
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def n31(a: int) -> Tuple[List[int], int]:
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"""
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Returns the Collatz sequence and its length of any postiver integer.
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>>> n31(4)
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([4, 2, 1], 3)
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"""
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if not isinstance(a, int):
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raise TypeError("Must be int, not {0}".format(type(a).__name__))
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if a < 1:
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raise ValueError("Given integer must be greater than 1, not {0}".format(a))
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path = [a]
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while a != 1:
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if a % 2 == 0:
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a = a // 2
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else:
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a = 3 * a + 1
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path += [a]
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return path, len(path)
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def main():
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num = 4
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path, length = n31(num)
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print(
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"The Collatz sequence of {0} took {1} steps. \nPath: {2}".format(
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num, length, path
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)
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)
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if __name__ == "__main__":
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main()
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