Amazon Online Assessment (OA) - Five Star Seller

An arborist that operates a plant store in Brooklyn, NY would like to improve their online sales by improving their ratings.

In order to become a five-star store, they must maintain a certain threshold percentage of five-star ratings. Given their current situation, find the minimum number of additional five-star ratings they must receive to meet the threshold. The overall online store percentage is calculated by taking the sum of percentages of five-star ratings for each product.

Examples

Example 1:

Input:

productCount = 3

productRatings = [[4,4],[1,2],[3,6]] where each entry is [five-star reviews, total reviews]

threshold = 77

Output: 3
Explanation :

We need the sum of the percentages of five-star ratings for each product to add up to the threshold.

The current percentage of five-star ratings for this seller is ((4/4) + (1/2) + (3/6))/3 = 66.66%

If we add a five star review to product #2, their threshold becomes ((4/4) + (2/3) + (3/6))/3 = 72.22%

If we add another five star review to product #2, their threshold becomes ((4/4) + (3/4) + (3/6))/3 = 75%

If we add a five star review to product #3, their threshold becomes ((4/4) + (3/4) + (4/7))/3 = 77.38%

At this point, the 77% threshold is met. The answer is 3, because there is no other way to add less ratings and achieve 77% or more.

Constraints:

There is always at least one product, and the threshold is between 1 and 99 inclusive. All values are positive.

Try it yourself

Solution