Counting steps to make number palindrome in JavaScript

JavascriptWeb DevelopmentFront End Technology

Problem

We are required to write a JavaScript function that takes in a number, num, as the first and the only argument.

Our function should return the number of special steps needed to obtain a palindrome. The special step is: "reverse the digits, and add to the original number". If the resulting number is not a palindrome, repeat the procedure with the sum until the resulting number is a palindrome.

For example, if the input to the function is −

Input

const num = 87;

Output

const output = 4;

Output Explanation

Because the steps involved are −

87 + 78 = 165; 165 + 561 = 726; 726 + 627 = 1353; 1353 + 3531 = 4884

Example

Following is the code −

 Live Demo

const num = 87;
const countSteps = (num) => {
   let res = 0;
   while (!isPalindrome(num)) {
   res++
   num += +('' + num).split``.reverse().join``
};
   return res;
}
const isPalindrome = num => {
   let i = 0
   let str = '' + num
   while (i++ <= str.length / 2) {
      if (str[i] !== str[str.length - 1 - i]) return false
   };
   return true
}
console.log(countSteps(num));

Output

4
raja
Published on 22-Apr-2021 10:17:34
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