Codeforces 932A Palindromic Supersequence (Super Water)

topic:

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

inputCopy
aba
output
aba
inputCopy
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.

Title:

There are two strings a, b; it is known that a is a substring of b and b is a palindrome string. Now give the string a and let you find the string b.

Ideas:

Because here is to randomly output a b that satisfies the condition, so directly output the positive and negative of a twice.

Code:

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <cmath>

using namespace std;
const int N=1e5+10;
char a[N];

int main()
{
    ios::sync_with_stdio(false);
    int n;
    while(cin>>a)
    {
        cout<<a;//正着输出一遍
        for(int i=strlen(a)-1;i>=0;i--)//逆过来再输出一遍
            cout<<a[i];
        cout<<endl;
    }
    return 0;
}