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Solution: Next Palindrome Using Same Digits

Explore how to use the two-pointer technique to find the next smallest palindrome larger than a given numeric palindrome by rearranging its digits. Understand splitting the number, finding the next lexicographical permutation of the left half, and mirroring it to create the solution. This lesson equips you with an efficient O(n) approach to solve palindrome rearrangement problems.

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Statement

Given a numeric string, numStr, representing a palindromeA palindrome is a number that reads the same backward as it does forward. (composed only of digits). Return the smallest palindrome larger than numStr that can be created by rearranging its digits. If no such palindrome exists, return an empty string "".

Consider the following example to understand the expected output for a given numeric string:

  • input string = "123321"

  • The valid palindromes made from the exact digits are "213312", "231132", "312213", "132231", "321123".

  • We return the palindrome "132231" because it is the smallest palindrome larger than the input string "123321".

Constraints:

  • ...