ca6bd29ed8
InterviewCake asks "How would you handle punctuation?". Without precise specs about what that entails, I'm supporting sentences ending with punctuation.
74 lines
2 KiB
Python
74 lines
2 KiB
Python
import unittest
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def reverse(xs, i, j):
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"""Reverse array of characters, xs, in-place."""
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while i < j:
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xs[i], xs[j] = xs[j], xs[i]
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i += 1
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j -= 1
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def reverse_words(xs):
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punctuation = None
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if len(xs) > 0 and xs[-1] in ".?!":
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punctuation = xs.pop()
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reverse(xs, 0, len(xs) - 1)
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i = 0
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j = i
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while j < len(xs):
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while j < len(xs) and xs[j] != ' ':
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j += 1
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reverse(xs, i, j - 1)
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j += 1
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i = j
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if punctuation:
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xs.append(punctuation)
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# Tests
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class Test(unittest.TestCase):
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def test_one_word(self):
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message = list('vault')
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reverse_words(message)
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expected = list('vault')
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self.assertEqual(message, expected)
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def test_two_words(self):
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message = list('thief cake')
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reverse_words(message)
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expected = list('cake thief')
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self.assertEqual(message, expected)
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def test_three_words(self):
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message = list('one another get')
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reverse_words(message)
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expected = list('get another one')
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self.assertEqual(message, expected)
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def test_multiple_words_same_length(self):
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message = list('rat the ate cat the')
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reverse_words(message)
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expected = list('the cat ate the rat')
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self.assertEqual(message, expected)
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def test_multiple_words_different_lengths(self):
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message = list('yummy is cake bundt chocolate')
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reverse_words(message)
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expected = list('chocolate bundt cake is yummy')
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self.assertEqual(message, expected)
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def test_empty_string(self):
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message = list('')
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reverse_words(message)
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expected = list('')
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self.assertEqual(message, expected)
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def test_bonus_support_punctuation(self):
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message = list('yummy is cake bundt chocolate this!')
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reverse_words(message)
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expected = list('this chocolate bundt cake is yummy!')
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self.assertEqual(message, expected)
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unittest.main(verbosity=2)
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