Question:

Determine whether an integer is a palindrome. Do this without extra
space.

Some hints:

Could negative integers be palindromes? (ie, -1)

If you are thinking of converting the integer to string, note the
restriction of using extra space.

You could also try reversing an integer. However, if you have solved the
problem "Reverse Integer", you know that the reversed integer might
overflow. How would you handle such case?

There is a more generic way of solving this problem.