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.
public boolean isPalindrome(int x) {
if (x < 0) {
return false;
}
if (x >= 0 && x < 10) {
return true;
}
int d = 1;
while (x / d >= 10) {
d *= 10;
}
while (x != 0) {
if (x % 10 != x / d) {
return false;
}
x = x % d / 10;
d /= 100;
}
return true;
}
