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.
91 lines
2.7 KiB
Python
91 lines
2.7 KiB
Python
import unittest
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################################################################################
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# Implementation
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################################################################################
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def is_first_come_first_served(to, di, xs):
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# All the guards, assertions we should need.
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if to == di == xs == []:
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return True
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elif to == di == []:
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return False
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elif to == []:
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return di == xs
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elif to == []:
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return di == xs
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elif di == []:
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return to == xs
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elif xs == []:
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return False
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elif len(xs) != (len(to) + len(di)):
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return False
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fst, snd = to, di
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if xs[0] == to[0]:
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fst, snd = to, di
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elif xs[0] == di[0]:
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fst, snd = di, to
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else:
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return False
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fst_done, snd_done = False, False
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fi, si = 1, 0
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for i in range(1, len(xs)):
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# Short-circuit and avoid index-out-of-bounds without introducing overly
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# defensive, sloppy code.
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if fst_done:
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return snd[si:] == xs[i:]
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elif snd_done:
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return fst[fi:] == xs[i:]
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if fst[fi] == xs[i]:
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fi += 1
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elif snd[si] == xs[i]:
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si += 1
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else:
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return False
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fst_done, snd_done = fi == len(fst), si == len(snd)
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return True
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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_both_registers_have_same_number_of_orders(self):
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result = is_first_come_first_served([1, 4, 5], [2, 3, 6],
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[1, 2, 3, 4, 5, 6])
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self.assertTrue(result)
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def test_registers_have_different_lengths(self):
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result = is_first_come_first_served([1, 5], [2, 3, 6], [1, 2, 6, 3, 5])
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self.assertFalse(result)
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def test_one_register_is_empty(self):
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result = is_first_come_first_served([], [2, 3, 6], [2, 3, 6])
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self.assertTrue(result)
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def test_served_orders_is_missing_orders(self):
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result = is_first_come_first_served([1, 5], [2, 3, 6], [1, 6, 3, 5])
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self.assertFalse(result)
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def test_served_orders_has_extra_orders(self):
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result = is_first_come_first_served([1, 5], [2, 3, 6],
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[1, 2, 3, 5, 6, 8])
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self.assertFalse(result)
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def test_one_register_has_extra_orders(self):
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result = is_first_come_first_served([1, 9], [7, 8], [1, 7, 8])
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self.assertFalse(result)
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def test_one_register_has_unserved_orders(self):
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result = is_first_come_first_served([55, 9], [7, 8], [1, 7, 8, 9])
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self.assertFalse(result)
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unittest.main(verbosity=2)
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