The title

Given an integer x, return true if x is a palindrome; Otherwise, return false.

Palindromes are integers that are read in the same order (from left to right) and in the same order (from right to left). For example, 121 is a palindrome, while 123 is not.

Example 1:

Input: x = 121 Output: trueCopy the code

Example 2:

Input: x = -121 Output: false Description: Read -121 from left to right. Read from right to left: 121-. So it's not a palindrome number.Copy the code

Example 3:

Input: x = 10 Output: false Description: Read from right to left, as 01. So it's not a palindrome number.Copy the code

Example 4:

Input: x = -101 Output: falseCopy the code

Tip:

-231 <= x <= 231 - 1
Copy the code

implementation

Just turn the numbers around and see if the numbers before and after the comparison are the same.

class Solution {
    public boolean isPalindrome(int x) {
        if (x < 0) return false;
        int temp = x, rev = 0;
        while (temp > 0){
            rev = rev * 10 + temp % 10;
            temp = temp / 10;
        }
        returnrev == x; }}Copy the code