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355
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1 def sign(i, assertions=True):
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2 """
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3 + or - 1
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4 @precondition: i != 0
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5 """
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6 if assertions:
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7 assert i != 0
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8 else:
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9 if i == 0: return 0
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10
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11 return +1 if i > 0 else -1
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12
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13 def percent_string(a, b):
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14 assert a <= b
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15 assert a >= 0
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16 assert b > 0
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17 return "%s of %s (%.2f%%)" % (a, b, 100.*a/b)
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18
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19 def unique_elements_list_intersection(list1,list2):
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20 """
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21 Return the unique elements that are in both list1 and list2
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22 (repeated elements in listi will not be duplicated in the result).
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23 This should run in O(n1+n2) where n1=|list1|, n2=|list2|.
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24 """
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25 return list(set.intersection(set(list1),set(list2)))
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