Problem

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:

Coud you solve it without converting the integer to a string?

Pre analysis

Will just match reversed string.

Another solution

1. Magical solution

   var isPalindrome = function(x) {
   if( x < 0 ){return false;}
   if( x < 10 ){return true;}
   if( x % 10 === 0){return false;}
   var z = x;
   var f = 0;
   
   while(f < z){
       var f = f \* 10 + z % 10;
       var z = ~~(z / 10);
   
       if( z === f || ~~(z/10) === f ){
        return true;
       }
   
       }
   
       return false;
   
   }
   

2. Optimised Approach

   var isPalindrome = function(x) {
       const val = x.toString()
       const last = val.length - 1;
       const middle = Math.floor(last / 2)
   
       for (let i = 0; i <= middle; i++) {
           if (val[i] !== val[last - i]) {
               return false;
           }
       }
   
       return true;
   };