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Grokking the Coding Interview Patterns in Go

Solution: Next Palindrome Using Same Digits

Explore how to find the smallest palindrome larger than a given numeric palindrome by rearranging digits. This lesson teaches you to use the two pointer technique to generate the next lexicographical permutation of half the string, then mirror it to form the next palindrome. Understand the steps to identify positions for swapping and rearranging digits, and how to handle even and odd length palindromes precisely. By mastering this, you will efficiently solve problems involving palindrome generation under constraints.

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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:

  • 1≤1 \leq ...