Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.
Example 1:
Input: 121
Output: true
Example 2:
Input: -121
Output: false
Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.
Example 3:
Input: 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.
Follow up:
Could you solve it without converting the integer to a string?
Solution:
class Solution {
public boolean isPalindrome(int x) {
if (x < 0 || x == Integer.MAX_VALUE) return false;
int reversed = 0;
int num = x;
while (num > 0) {
reversed = reversed * 10 + num % 10;
num /= 10;
}
return reversed == x;
}
}