can anyone give me any idea for this problem.
Problem: The Great Ball
| # | User | Rating |
|---|---|---|
| 1 | Benq | 3676 |
| 2 | Kevin114514 | 3657 |
| 3 | jiangly | 3638 |
| 4 | turmax | 3442 |
| 5 | tourist | 3380 |
| 6 | Um_nik | 3353 |
| 7 | strapple | 3350 |
| 8 | squareOf105 | 3346 |
| 9 | heuristica | 3322 |
| 10 | maroonrk | 3310 |
| # | User | Contrib. |
|---|---|---|
| 1 | Qingyu | 158 |
| 2 | nik_exists | 151 |
| 3 | maspy | 150 |
| 4 | AmShZ | 144 |
| 4 | Um_nik | 144 |
| 6 | Errichto | 139 |
| 7 | adamant | 137 |
| 8 | BledDest | 135 |
| 9 | maroonrk | 133 |
| 10 | Proof_by_QED | 131 |
can anyone give me any idea for this problem.
Problem: The Great Ball
| Name |
|---|



Store each entrance and exit as an event (a change in number of people which is +1 or -1, and a time the event occurs). Then process the events in order of time and keep track of the number of people after each event.