Palindrome Number LeetCode Cheat Sheet Javascript Solution

This LeetCode Challenge is really similar to the “reverse integer challenge” with a little spin. This time we want to return a boolean value.

The Palindrome challenge is in the easy category and is a good start for understanding more challenging algorithms. I will focus on explaining a solution that works and not on the O time and space complexity.

Palindrome Number Challenge

“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 palindrome while 123 is not.” (LeetCode)

Example
x= 565
return true
x= -565
became 565- therefore not a palindrome

1.Let create a reversed version of x

const reversed = (x+””).split(‘’).reverse().join(‘’);

a)Convert the number into a string ex 565 became “565”

(x+””)

b)Split the string ex “565” became “5”,”6",”5"

.split(‘’)

c)Reverse the split string ex “5”,”6",”5" became “5”,”6",”5"

.reverse()

d)Join method will create a string by concatenating the elements of the array ex “5”,”6",”5" became “565”

.join(‘’)

2.compare is x.toString is strictly equal to its reversed version.

When using a comparison sign the result would be a boolean value, true or false.

return (x.toString() === reversed)

In our case, it will return true

Solution

var isPalindrome = function(x) {
const reversed = (x+””).split(‘’).reverse().join(‘’);
return (x.toString() === reversed);
};