1842. Next Palindrome Using Same Digits

English Version

题目描述

You are given a numeric string num, representing a very large palindrome.

Return the smallest palindrome larger than num that can be created by rearranging its digits. If no such palindrome exists, return an empty string "".

A palindrome is a number that reads the same backward as forward.

 

Example 1:

Input: num = "1221"

Output: "2112"

Explanation: The next palindrome larger than "1221" is "2112".

Example 2:

Input: num = "32123"

Output: ""

Explanation: No palindromes larger than "32123" can be made by rearranging the digits.

Example 3:

Input: num = "45544554"

Output: "54455445"

Explanation: The next palindrome larger than "45544554" is "54455445".

 

Constraints:

• 1 <= num.length <= 105
• num is a palindrome.

解法

Python3

Java

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