arrayOfProduct

/**
 * Write a function that takes in a non-empty array of integers and returns an array of same length,
 * where each element in the output array is equal to the product of every other number in the input array.
 */

export default function arrayOfProduct(arr) {
  const products = new Array(arr.length).fill(1);

  let leftRunningProduct = 1;
  for (let i = 0; i < arr.length; i++) {
    products[i] = leftRunningProduct;
    leftRunningProduct *= arr[i];
  }

  let rightRunningProduct = 1;
  for (let i = arr.length - 1; i >= 0; i--) {
    products[i] *= rightRunningProduct;
    rightRunningProduct *= arr[i];
  }

  return products;
}

// Input
// array=[5, 1, 4, 2]
// Output
// [8, 40, 10, 20]