2090. Short Palindromes

单点时限: 2.0 sec

内存限制: 256 MB

A palindrome is a String that is spelled the same forward and backwards. Given a String base that may or may not be a palindrome, we can always force base to be a palindrome by adding letters to it. For example, given the word “RACE”, we could add the letters “CAR” to its back to get “RACECAR” (quotes for clarity only). However, we are not restricted to adding letters at the back. For example, we could also add the letters “ECA” to the front to get “ECARACE”. In fact, we can add letters anywhere in the word, so we could also get “ERCACRE” by adding an ‘E’ at the beginning, a ‘C’ after the ‘R’, and another ‘R’ before the final ‘E’. Your task is to make base into a palindrome by adding as few letters as possible and return the resulting String. When there is more than one palindrome of minimal length that can be made, return the lexicographically earliest (that is, the one that occurs first in alphabetical order).

输入格式

There are many test cases!Each line a string.

-base contains between 1 and 25 characters, inclusive.

-Every character in base is an uppercase letter (‘A’-‘Z’).

输出格式

Your task is to make base into a palindrome by adding as few letters as possible and return the resulting String.

样例

Input
RACE
Output
ECARACE
To make "RACE" into a palindrome, we must add at least three letters. However, there are eight ways to do this by adding exactly three letters:
"ECARACE" "ECRARCE" "ERACARE" "ERCACRE"
"RACECAR" "RAECEAR" "REACAER" "RECACER"
Of these alternatives, "ECARACE" is the lexicographically earliest.

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8 份提交通过,共有 17 份提交。

7.0 EMB 奖励。

创建: 11 年,8 月前.

修改: 2 年,6 月前.

最后提交: 1 年,11 月前.

来源: TC

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