We are required to write a JavaScript function that takes in an array and a number n.
Our function should rotate the array by n elements, i.e., take n elements from the front and put them to the end.
The only condition here is that we have to do this without using any extra space in memory −
For example −
If the input array is the following,
const arr = [12, 6, 43, 5, 7, 2, 5];
and number n is 3, then the output should be;
const output = [5, 7, 2, 5, 12, 6, 43];
Example
Following is the code −
const arr = [12, 6, 43, 5, 7, 2, 5];
const num = 5;
const rotateByOne = arr => {
for(let i = 0; i < arr.length-1; i++){
temp = arr[i];
arr[i] = arr[i+1];
arr[i+1] = temp;
};
}
Array.prototype.rotateBy = function(n){
const { length: l } = this;
if(n >= l){
return;
};
for(let i = 0; i < n; i++){
rotateByOne(this);
};
};
arr.rotateBy(num);
console.log(arr);Output
This will produce the following output in console −
[ 2, 5, 12, 6, 43, 5, 7 ]