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题库练习 Palindrome

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A9110 | $Palindrome$

时间限制1s

内存限制256MB

通过 / 提交0/0

题目描述

Given a string $s$ , determine if it contains any palindrome of length exactly $100$ as a subsequence. If it has any, print any one of them. If it doesn't have any, print a palindrome that is a subsequence of $s$ and is as long as possible.

输入格式

The only line of the input contains one string $s$ of length $n$ ( $1<=n<=5·10^{4}$ ) containing only lowercase English letters.

输出格式

If $s$ contains a palindrome of length exactly $100$ as a subsequence, print any palindrome of length $100$ which is a subsequence of $s$ . If $s$ doesn't contain any palindromes of length exactly $100$ , print a palindrome that is a subsequence of $s$ and is as long as possible. If there exists multiple answers, you are allowed to print any of them.

输入输出样例

输入 #1

bbbabcbbb

输出 #1

bbbcbbb

输入 #2

rquwmzexectvnbanemsmdufrg

输出 #2

rumenanemur

C++ 编辑器

输入

输出