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.
68 lines
2.2 KiB
Python
68 lines
2.2 KiB
Python
import unittest
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################################################################################
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# Solution
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################################################################################
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# f :: [Int] -> [Int]
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def get_products_of_all_ints_except_at_index(xs):
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if len(xs) in {0, 1}:
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raise Exception
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ct = len(xs)
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lefts = [1] * ct
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rights = [1] * ct
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result = []
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for i in range(1, ct):
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lefts[i] = lefts[i - 1] * xs[i - 1]
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for i in range(ct - 2, -1, -1):
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rights[i] = rights[i + 1] * xs[i + 1]
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return [lefts[i] * rights[i] for i in range(ct)]
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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_small_list(self):
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actual = get_products_of_all_ints_except_at_index([1, 2, 3])
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expected = [6, 3, 2]
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self.assertEqual(actual, expected)
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def test_longer_list(self):
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actual = get_products_of_all_ints_except_at_index([8, 2, 4, 3, 1, 5])
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expected = [120, 480, 240, 320, 960, 192]
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self.assertEqual(actual, expected)
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def test_list_has_one_zero(self):
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actual = get_products_of_all_ints_except_at_index([6, 2, 0, 3])
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expected = [0, 0, 36, 0]
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self.assertEqual(actual, expected)
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def test_list_has_two_zeros(self):
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actual = get_products_of_all_ints_except_at_index([4, 0, 9, 1, 0])
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expected = [0, 0, 0, 0, 0]
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self.assertEqual(actual, expected)
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def test_one_negative_number(self):
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actual = get_products_of_all_ints_except_at_index([-3, 8, 4])
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expected = [32, -12, -24]
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self.assertEqual(actual, expected)
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def test_all_negative_numbers(self):
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actual = get_products_of_all_ints_except_at_index([-7, -1, -4, -2])
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expected = [-8, -56, -14, -28]
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self.assertEqual(actual, expected)
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def test_error_with_empty_list(self):
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with self.assertRaises(Exception):
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get_products_of_all_ints_except_at_index([])
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def test_error_with_one_number(self):
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with self.assertRaises(Exception):
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get_products_of_all_ints_except_at_index([1])
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unittest.main(verbosity=2)
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