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authorVincent Ambo <mail@tazj.in>2021-12-13T22·51+0300
committerVincent Ambo <mail@tazj.in>2021-12-13T23·15+0300
commit019f8fd2113df4c5247c3969c60fd4f0e08f91f7 (patch)
tree76a857f61aa88f62a30e854651e8439db77fd0ea /users/wpcarro/scratch/deepmind/part_two/reverse-words.py
parent464bbcb15c09813172c79820bcf526bb10cf4208 (diff)
parent6123e976928ca3d8d93f0b2006b10b5f659eb74d (diff)
subtree(users/wpcarro): docking briefcase at '24f5a642' r/3226
git-subtree-dir: users/wpcarro
git-subtree-mainline: 464bbcb15c09813172c79820bcf526bb10cf4208
git-subtree-split: 24f5a642af3aa1627bbff977f0a101907a02c69f
Change-Id: I6105b3762b79126b3488359c95978cadb3efa789
Diffstat (limited to 'users/wpcarro/scratch/deepmind/part_two/reverse-words.py')
-rw-r--r--users/wpcarro/scratch/deepmind/part_two/reverse-words.py74
1 files changed, 74 insertions, 0 deletions
diff --git a/users/wpcarro/scratch/deepmind/part_two/reverse-words.py b/users/wpcarro/scratch/deepmind/part_two/reverse-words.py
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+++ b/users/wpcarro/scratch/deepmind/part_two/reverse-words.py
@@ -0,0 +1,74 @@
+import unittest
+
+
+def reverse(xs, i, j):
+    """Reverse array of characters, xs, in-place."""
+    while i < j:
+        xs[i], xs[j] = xs[j], xs[i]
+        i += 1
+        j -= 1
+
+
+def reverse_words(xs):
+    punctuation = None
+    if len(xs) > 0 and xs[-1] in ".?!":
+        punctuation = xs.pop()
+    reverse(xs, 0, len(xs) - 1)
+    i = 0
+    j = i
+    while j < len(xs):
+        while j < len(xs) and xs[j] != ' ':
+            j += 1
+        reverse(xs, i, j - 1)
+        j += 1
+        i = j
+    if punctuation:
+        xs.append(punctuation)
+
+
+# Tests
+class Test(unittest.TestCase):
+    def test_one_word(self):
+        message = list('vault')
+        reverse_words(message)
+        expected = list('vault')
+        self.assertEqual(message, expected)
+
+    def test_two_words(self):
+        message = list('thief cake')
+        reverse_words(message)
+        expected = list('cake thief')
+        self.assertEqual(message, expected)
+
+    def test_three_words(self):
+        message = list('one another get')
+        reverse_words(message)
+        expected = list('get another one')
+        self.assertEqual(message, expected)
+
+    def test_multiple_words_same_length(self):
+        message = list('rat the ate cat the')
+        reverse_words(message)
+        expected = list('the cat ate the rat')
+        self.assertEqual(message, expected)
+
+    def test_multiple_words_different_lengths(self):
+        message = list('yummy is cake bundt chocolate')
+        reverse_words(message)
+        expected = list('chocolate bundt cake is yummy')
+        self.assertEqual(message, expected)
+
+    def test_empty_string(self):
+        message = list('')
+        reverse_words(message)
+        expected = list('')
+        self.assertEqual(message, expected)
+
+    def test_bonus_support_punctuation(self):
+        message = list('yummy is cake bundt chocolate this!')
+        reverse_words(message)
+        expected = list('this chocolate bundt cake is yummy!')
+        self.assertEqual(message, expected)
+
+
+unittest.main(verbosity=2)