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@newmanbrad
Created December 29, 2016 14:29
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Puzzle Question and answer.
/***
Number is a palindrome if it is equal to the number with digits in reversed order. For example, 5, 44, 171, 4884 are palindromes and 43, 194, 4773 are not palindromes.
Write a method palindrome_chain_length which takes a positive number and returns 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.
If the input number is already a palindrome, the number of steps is 0.
Input will always be a positive integer.
For example, start with 87:
87 + 78 = 165; 165 + 561 = 726; 726 + 627 = 1353; 1353 + 3531 = 4884
4884 is a palindrome and we needed 4 steps to obtain it, so palindrome_chain_length(87) == 4
***/
var palindromeChainLength = function(n, count = 0) {
let combinedNumber = n + parseInt(n.toString().split('').reverse().join(''));
let isPalindrome = (combinedNumber == parseInt(combinedNumber.toString().split('').reverse().join('')));
if(!isPalindrome && n.toString().split('').length > 1){
palindromeChainLength(combinedNumber, ++count);
} else {
return count;
}
};
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