HackerLand Enterprise is adopting a new viral advertising strategy. When they launch a new product, they advertise it to exactly 5 people on social media.
On the first day, half of those 5 people (i.e., floor(5/2) = 2) like the advertisement and each shares it with 3 of their friends. At the beginning of the second day, floor(5 / 2) * 3 = 6 people receive the advertisement.
Each day, floor(recipient/2) of the recipients like the advertisement and will share it with 3 friends on the following day. Assuming nobody receives the advertisement twice, determine how many people have liked the ad by the end of a given day, beginning with launch day as day 3.
[in]
5
[out]
24
| Day | Shared | Liked | Cumulative |
|---|---|---|---|
| 1 | 5 | 2 | 2 |
| 2 | 6 | 3 | 5 |
| 3 | 9 | 4 | 9 |
| 4 | 12 | 6 | 15 |
| 5 | 18 | 9 | 24 |
The progression is shown above. The cumulative number of likes on the 5 day is 24.