CF463 A题Palindromic Supersequence

最新推荐文章于 2021-07-20 10:47:41 发布

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最新推荐文章于 2021-07-20 10:47:41 发布

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本文介绍了一种算法，用于将给定的字符串转换为回文形式的超序列，确保原字符串为新序列的子序列，并且长度不超过10^4。通过判断原字符串是否为回文来决定直接输出还是进行转换。

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You are given a string A. Find a string B, where B is a palindrome and A is a subsequence of B.

A subsequence of a string is a string that can be derived from it by deleting some (not necessarily consecutive) characters without changing the order of the remaining characters. For example, "cotst" is a subsequence of "contest".

A palindrome is a string that reads the same forward or backward.

The length of string B should be at most 104. It is guaranteed that there always exists such string.

You do not need to find the shortest answer, the only restriction is that the length of string B should not exceed 104.

Input

First line contains a string A (1 ≤ |A| ≤ 103) consisting of lowercase Latin letters, where |A| is a length of A.

Output

Output single line containing B consisting of only lowercase Latin letters. You do not need to find the shortest answer, the only restriction is that the length of string B should not exceed 104. If there are many possible B, print any of them.

Examples
input
aba
output
aba
input
ab
output
aabaa

Note

In the first example, "aba" is a subsequence of "aba" which is a palindrome.

In the second example, "ab" is a subsequence of "aabaa" which is a palindrome.

题意是给出一个字符串A，判断它是否回文，是的话输出，否则把它变成回文再输出。

#include<iostream>
#include<cstring>
#include<string>
using namespace std;
int judge(string a)
{ int l=a.length();
    for(int i=0;i<l;i++)
    {
        if(a[i]==a[l-i-1])
        {

        }
        else return 0;
        if(i==l/2+1)
            return 1;
    }
    return 1;
}
int main()
{
string a;
string b;
string c;
cin>>a;
b.assign(a.rbegin(),a.rend());
if(judge(a))
    cout<<a<<endl;
else
{
c=a+b;
if(c.length()<10000)
cout<<c<<endl;

}
return 0;
}