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28 lines
1.2 KiB
Python
28 lines
1.2 KiB
Python
#!/bin/python
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"""
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Write a function to tell us if a full deck of cards shuffled_deck is a single riffle of two other halves half1 and half2.
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We'll represent a stack of cards as a list of integers in the range 1..521..52 (since there are 5252 distinct cards in a deck).
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Why do I care? A single riffle is not a completely random shuffle. If I'm right, I can make more informed bets and get rich and finally prove to my ex that I am not a "loser with an unhealthy cake obsession" (even though it's too late now because she let me go and she's never getting me back).
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"""
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def is_single_riffle(half1, half2, shuffled_deck,
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shuffled_deck_index=0, half1_index=0, half2_index=0):
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if shuffled_deck_index == len(shuffled_deck):
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return True
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if ((half1_index < len(half1)) and
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half1[half1_index] == shuffled_deck[shuffled_deck_index]):
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half1_index += 1
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elif ((half2_index < len(half2)) and
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half2[half2_index] == shuffled_deck[shuffled_deck_index]):
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half2_index += 1
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else:
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return False
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shuffled_deck_index += 1
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return is_single_riffle(
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half1, half2, shuffled_deck, shuffled_deck_index,
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half1_index, half2_index) |