5. Longest Palindromic Substring 最长的回文子串

Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000.

Example:

Input: "babad"

Output: "bab"

Note: "aba" is also a valid answer.

Example:

Input: "cbbd"

Output: "bb"

class Solution1:

def longestPalindrome(self, s):

"""

:type s: str

:rtype: str

"""

res = ""

for i in range(len(s)):

j = i + len(res) + 1

while j <= len(s):

cur = s[i:j]

if len(cur) > len(res) and cur == cur[::-1]:

res = cur

j += 1

return res

class Solution2:

def longestPalindrome(self, s):

if len(s) == 0:

return ""

maxLen = 1

start = 0

for i in range(len(s)):

cur = s[i - maxLen - 1:i + 1]

if i - maxLen >= 1 and cur == cur[::-1]:

start = i - maxLen - 1

maxLen += 2

continue

cur = s[i - maxLen:i + 1]

if i - maxLen >= 0 and cur == cur[::-1]:

start = i - maxLen

maxLen += 1

return s[start:start + maxLen]

s = "babad"

#s = "cbbd"

solution = Solution2()

res = solution.longestPalindrome(s)

# print(res)

来自为知笔记(Wiz)

原文地址：https://www.cnblogs.com/xiejunzhao/p/8445814.html

时间： 2024-08-26 11:50:57

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