Merge branch 'master' into 2128#issuecomment-703119780-maintainability

strings/manacher.py

@@ -1,57 +1,57 @@
-import unittest
-
-
-def longest_palindromic_substring(string: str) -> str:
-    """
-    Manacher’s algorithm which finds Longest Palindromic Substring.
-    Source: https://en.wikipedia.org/wiki/Longest_palindromic_substring
-    """
-    if string == "":
-        return ""
-
-    # create string with separators: "aba" -> "a|b|a"
-    new_string = "|".join(list(string))
-
-    left = right = 0  # start/end index of longest palindrome so far
-    # length[i] shows the length of palindromic substring with center i
-    length = [1] * len(new_string)
-    start = max_length = 0
-
-    # for each character in new_string find the corresponding max palindrome length
-    #   and store the length and left, right boundary
-    for i, _ in enumerate(new_string):
-        k = 1 if i > right else min(length[left + right - i] // 2, right - i + 1)
-        while (
-            i - k >= 0
-            and i + k < len(new_string)
-            and new_string[k + i] == new_string[i - k]
-        ):
-            k += 1
-
-        length[i] = 2 * k - 1
-
-        # update the right and left index if string ends after the previously right      
-        if i + k - 1 > right:
-            left = i - k + 1  # noqa: E741
-            right = i + k - 1
-
-        if max_length < length[i]:
-            max_length = length[i]
-            start = i
-
-    s = new_string[start - max_length // 2 : start + max_length // 2 + 1]
-    return "".join(s.split("|"))
-
-
-class TestLongestPalindrome(unittest.TestCase):
-    def test_longest_palindromic_substring(self):
-        self.assertEqual(longest_palindromic_substring("abbbaba"), "abbba")
-        self.assertEqual(longest_palindromic_substring("ababa"), "ababa")
-        self.assertEqual(longest_palindromic_substring(""), "")
-        self.assertEqual(longest_palindromic_substring("a"), "a")
-        self.assertEqual(longest_palindromic_substring("aa"), "aa")
-        self.assertEqual(longest_palindromic_substring("abc"), "b")
-
-
-if __name__ == "__main__":
-    unittest.main()
+import unittest
+
+
+def longest_palindromic_substring(string: str) -> str:
+    """
+    Manacher’s algorithm which finds Longest Palindromic Substring.
+    Source: https://en.wikipedia.org/wiki/Longest_palindromic_substring
+    """
+    if string == "":
+        return ""
+
+    # create string with separators: "aba" -> "a|b|a"
+    new_string = "|".join(list(string))
+
+    left = right = 0  # start/end index of longest palindrome so far
+    # length[i] shows the length of palindromic substring with center i
+    length = [1] * len(new_string)
+    start = max_length = 0
+
+    # for each character in new_string find the corresponding max palindrome length
+    #   and store the length and left, right boundary
+    for i, _ in enumerate(new_string):
+        k = 1 if i > right else min(length[left + right - i] // 2, right - i + 1)
+        while (
+            i - k >= 0
+            and i + k < len(new_string)
+            and new_string[k + i] == new_string[i - k]
+        ):
+            k += 1
+
+        length[i] = 2 * k - 1
+
+        # update the right and left index if string ends after the previously right      
+        if i + k - 1 > right:
+            left = i - k + 1  # noqa: E741
+            right = i + k - 1
+
+        if max_length < length[i]:
+            max_length = length[i]
+            start = i
+
+    s = new_string[start - max_length // 2 : start + max_length // 2 + 1]
+    return "".join(s.split("|"))
+
+
+class TestLongestPalindrome(unittest.TestCase):
+    def test_longest_palindromic_substring(self):
+        self.assertEqual(longest_palindromic_substring("abbbaba"), "abbba")
+        self.assertEqual(longest_palindromic_substring("ababa"), "ababa")
+        self.assertEqual(longest_palindromic_substring(""), "")
+        self.assertEqual(longest_palindromic_substring("a"), "a")
+        self.assertEqual(longest_palindromic_substring("aa"), "aa")
+        self.assertEqual(longest_palindromic_substring("abc"), "b")
+
+
+if __name__ == "__main__":
+    unittest.main()