It’s Friday, so it’s time to get comfortable, weekend is coming 🙌, and for today we have a very easy JCC (JavaScript Coding Challenge)!

Here is another easy, and beautiful 😇 challenge from HackerRank:

Lily likes to play games with integers. She has created a new game where she determines the difference between a number and its reverse. For instance, given the number

`12`

, its reverse is`21`

. Their difference is`9`

. The number`120`

reversed is`21`

, and their difference is`99`

.She decides to apply her game to decision making. She will look at a numbered range of days and will only go to a movie on a beautiful day.

Given a range of numbered days,

`[i...j]`

and a number`k`

, determine the number of days in the range that arebeautiful. Beautiful numbers are defined as numbers where`|i - reverse(i)|`

is evenly divisible by`k`

. If a day’s value is a beautiful number, it is a beautiful day. Print the number of beautiful days in the range.

## Function Description

Create a

`beautifulDays`

function. It must return the number ofbeautiful daysin the range.

`beautifulDays`

has the following parameters:

`i`

: the starting day number`j`

: the ending day number`k`

: the divisor

Isn’t this challenge **beautiful**? 😇

### The solution

Let’s break the problem into smaller pieces. We’ll have to:

- Loop through all the numbers from
`i`

to`j`

- Get the difference between the
**number**and its**reverse** - Determine if the difference is evenly divisible by
`k`

`Count`

the**beautiful**numbers- Return the
`count`

```
function beautifulDays(i, j, k) {
let count = 0;
// Step 1.
for (let x = i; x <= j; x++) {
// Step 4.
if (isBeautifulDay(x, k)) {
count++;
}
}
// Step 5.
return count;
}
function isBeautifulDay(x, k) {
// Step 3.
return differenceOfReverse(x) % k === 0;
}
function differenceOfReverse(x) {
let reversedX = parseInt(
x
.toString()
.split('')
.reverse()
.join('')
);
// Step 2.
return Math.abs(x - reversedX);
}
```

I decided to split the solution in multiple functions. It’s easier to understand what’s going on this way.

Everything from the code above is pretty clear, but I do want to go over how we reverse the number.

Let’s work on an **example** number, let’s say: `120`

. So we have: `let x = 120;`

.

### Convert it to a string

```
x.toString(); // result: '120'
```

### Split the string into an array of characters

```
x.toString().split(''); // result: ['1', '2', '0']
```

### Reverse the array

```
x.toString()
.split('')
.reverse(); // result: ['0', '2', '1']
```

### Join the characres from te array back to a string

```
x.toString()
.split('')
.reverse()
.join(''); // result: '021'
```

### Convert the string back to a number

```
parseInt(
x
.toString()
.split('')
.reverse()
.join('')
); // result: 21
```

Voila! We have the reversed number!

## Conclusion

Nothing fancy for today, but at the same time we had a chance to complete a challenge.

**REMEMBER**: even if you don’t work a lot in a day for your dream, it’s important to do something **EVERY SINGLE DAY**! Keep moving forward everyday even if it’s only a single small step! 😉 These small steps will pile up in something big one day!