MediumStrings
Longest Palindromic Substring
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Given a string s, return the longest palindromic substring in s.
A palindrome is a string that reads the same forward and backward.
Example 1:
Input: s = "babad"
Output: "bab"
Explanation: "aba" is also a valid answer.
Example 2:
Input: s = "cbbd"
Output: "bb"
Example 3:
Input: s = "a"
Output: "a"
Examples
Example 1
Input: s = "babad"
Output: "bab"
Explanation: "bab" is a palindromic substring of length 3. "aba" is also a valid answer.
Example 2
Input: s = "cbbd"
Output: "bb"
Explanation: "bb" is the longest palindromic substring with length 2.
Constraints
- -1 <= s.length <= 1000
- -s consist of only digits and English letters.
Optimal Complexity
Time
O(n^2)
Space
O(1)
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