Number theory Uvalive 2889

This is an examination of the problem of palindrome number, asking you to output the K palindrome number. In the process of doing the problem, we can find the regularity of the distribution of palindrome number: one number: 9, two digits: 9, three digits: 90, four digits: 90, five digits: 900, six digits: 900 ...

#include <iostream>
#include <cmath>
#include <cstring>
#include <cstdio>
int main ()
{
int n;
while (scanf ("%d", &n) &&n)
{
Long Long x=0;
while (n>x*2)
x=x*10+9;
if (N>X+X/10)
{
N-=x;
printf ("%d", n);
while (n>0)
{
printf ("%d", n%10);
n/=10;
}
}
Else
{
N-=X/10;
printf ("%d", n);
n/=10;
while (n>0)
{
printf ("%d", n%10);
n/=10;
}
}
printf ("\ n");
}
return 0;
}

Number theory Uvalive 2889