loop inside loop over one array

Question

I have the following code:

const arr = Array.from({length: 5}, (_, i) => i + 1);
const finalArray = [];
for (let i = 0; i < arr.length; i++) {
   for (let j = 0; j < arr.length; j++) {
       finalArray.push(arr[i] + '-' + arr[j])
   }
}

console.log(finalArray);

Which creates an array of range 1 => 5, and returns an array with a combination of all elements in the original array.

This code runs in O(n²), is it possible to make it more efficient?

Answer 1

No

You cannot output \$\Theta(n^2)\$ items in \$o(n^2)\$ time. Output size is a trivial lower bound of any algorithms.