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Author: assassint2017

Longest Palindromic Substring/Longest_Palindromic_Substring.py

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+# 1004ms 77.20%
+# 基本思路是，对于每个字符和两个字符的中间，都可能成为一个回文子字符串的中心
+# 因此，使用线性的扫描，对每个中心进行查找
+class Solution:
+    def longestPalindrome(self, s):
+        """
+        :type s: str
+        :rtype: str
+        """
+        if not s:
+            return ''
+        len_str, max_length, index = len(s), 0, 0.5
+        while index < len_str - 1:
+            left = int(index - 0.5)
+            right = int(index) + 1
+            length = 1 if int(index) == index else 0
+            
+            while left >= 0 and right <= len_str - 1:
+                if s[left] == s[right]:
+                    length += 2
+                    if length > max_length:
+                        max_length = length
+                        max_sub_string = s[left:right + 1]
+                    left -= 1;right += 1
+                else:
+                    break
+            index += 0.5
+        return s[0] if max_length is 0 else max_sub_string