beautiful day at the movies hackerrank solution
const reversedNum = num => parseFloat(num.toString().split('').reverse().join('')) * Math.sign(num)
function beautifulDays(i, j, k) {
let count = 0;
for(let s=i;s<j+1;s++) {
if(((s - reversedNum(s))/k)%1===0) {
count++
}
}
return count
}