Question Link : https://leetcode.com/problems/valid-palindrome/

Difficulty: Easy

Premium: False

Question

A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers. Given a string s, return true …

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Question Link : https://leetcode.com/problems/longest-palindromic-substring/

Difficulty: Medium

Premium: False

Question

Given a string s, return the longest palindromic substring in s.   Example 1:

Input: s = "babad" Output: "bab" Explanation: "aba" is also a valid answer.

Example 2:

Input: s = "cbbd" Output: "bb"

Constraints:

1 <= s.length <= 1000 s …

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Question Link : https://leetcode.com/problems/palindrome-number/

Difficulty: Easy

Premium: False

Question

Given an integer x, return true if x is a palindrome, and false otherwise.   Example 1:

Input: x = 121 Output: true Explanation: 121 reads as 121 from left to right and from right to left.

Example 2:

Input …

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Question Link : https://leetcode.com/problems/longest-palindrome-by-concatenating-two-letter-words/

Difficulty: Medium

Question

You are given an array of strings words. Each element of words consists of two lowercase English letters. Create the longest possible palindrome by selecting some elements from words and concatenating them in any order. Each element can be selected …

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Question Link : https://leetcode.com/problems/palindromic-substrings/

Difficulty: Medium

Question

Given a string s, return the number of palindromic substrings in it. A string is a palindrome when it reads the same backward as forward. A substring is a contiguous sequence of characters within the string.   Example 1:

Input: s …

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