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Improve is_palindrome() to avoid index access every time.
author
TAKAHASHI Shuuji
date
(Dec 19, 2019, 8:51 AM +0900)
commit
32742329
3274232953f599ee51cfc4de9662c55fd327ab11
parent
8b5df0c9
8b5df0c90580d561b940661873c098183ffb14ff
+5
-6
+5
-6
problems/5.longest-palindromic-substring.py
+5
-6
problems/5.longest-palindromic-substring.py
···
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j += 1
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def is_palindrome(self, substring: str) -> bool:
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-
i = 0
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j = len(substring) - 1
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while i < j:
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if substring[i] != substring[j]:
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center_index = len(substring) // 2
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first_part = substring[:center_index + 1] # 'abc' for 'abcde'
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last_part = reversed(substring[center_index:]) # 'edc' for 'abcde'
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for c1, c2 in zip(first_part, last_part):
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if c1 != c2:
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return False
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i += 1
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j -= 1
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return True