Algorithm


Problem - Palindrome Number

URL - https://leetcode.com/problems/palindrome-number/

Level - Beginner

Details -

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

 

 

Code Examples

#1 Code Example with Javascript Programming

Code - Javascript Programming


/**
 * @param {number} x
 * @return {boolean}
 */
var isPalindrome = function(x) {
      /**
       * Solution 1 : JavaScript way
       */
      //   const reverseNumber = x.toString().split("").reverse().join("");
      //   return x == reverseNumber;

      /**
       * Solution 2: Traditional Programming way
       */
      let initialX = x,
        reverseNumber = 0;

      // Reverse the number.
      while (x != 0) {
        reverseNumber = parseInt(reverseNumber * 10 + parseInt(x % 10));
        x = parseInt(x / 10);
      }

      // Handle for negative numbers.
      if (initialX < 0) {
        return initialX === -1 * reverseNumber;
      }

      return initialX === reverseNumber;
};
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Input

x
+
cmd
121

Output

x
+
cmd
true

Demonstration


Leetcode - Palindrome Number Problem solution in Javascript Leetcode