9. Palindrome Number

Problem

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Given an integer x, return true if x is palindrome integer.

An integer is a palindrome when it reads the same backward as forward.

• For example, 121 is a palindrome while 123 is not.

Example 1:

Input: x = 121
Output: true
Explanation: 121 reads as 121 from left to right and from right to left.

Example 2:

Input: x = -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: x = 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.

Constraints:

• -231 <= x <= 231 - 1

Follow up: Could you solve it without converting the integer to a string?

Solution

/**
 * @param {number} x
 * @return {boolean}
 */
var isPalindrome = function(x) {
  if(x < 0) return false;
    
  const arr = (x + '').split('');
  const reverseArr = [...arr];

  reverseArr.reverse();

  const arr1 = arr.join("");
  const reverseArr1 = reverseArr.join("");

  return arr1 == reverseArr1;
};