d4d8397e5f
Adds some of the code I generated while studying for a role transfer at Google using the fantastic resource, InterviewCake.com. This work predates the mono-repo. I should think of ways to DRY up this code and the code in crack_the_coding_interview, but I'm afraid I'm creating unnecessary work for myself that way.
61 lines
1.7 KiB
Python
61 lines
1.7 KiB
Python
from math import floor
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import unittest
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################################################################################
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# Solution
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################################################################################
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def bounds(r):
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ct = len(r)
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if ct % 2 == 0:
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h = int(ct / 2)
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return ct, h
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else:
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h = floor(ct / 2)
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return ct, h
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def find_repeat(xs):
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ct, h = bounds(xs)
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rl = range(1, h + 1)
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rr = range(h + 1, ct)
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while True:
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nl = len([None for x in xs if x in rl])
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nr = len([None for x in xs if x in rr])
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branch = rl if nl > nr else rr
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if len(branch) == 1:
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return branch[0]
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ct, h = bounds(branch)
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rl = range(branch[0], branch[0])
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rr = range(branch[0] + h, branch[-1] + 1)
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raise Exception(
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'We could not find any duplicates in xs. Perhaps xs did not adhere to the usage contract.'
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)
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################################################################################
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# Tests
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################################################################################
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class Test(unittest.TestCase):
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def test_just_the_repeated_number(self):
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actual = find_repeat([1, 1])
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expected = 1
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self.assertEqual(actual, expected)
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def test_short_list(self):
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actual = find_repeat([1, 2, 3, 2])
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expected = 2
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self.assertEqual(actual, expected)
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def test_medium_list(self):
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actual = find_repeat([1, 2, 5, 5, 5, 5])
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expected = 5
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self.assertEqual(actual, expected)
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def test_long_list(self):
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actual = find_repeat([4, 1, 4, 8, 3, 2, 7, 6, 5])
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expected = 4
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self.assertEqual(actual, expected)
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unittest.main(verbosity=2)
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