Most people on the floor at once
The register logs every staff entry (start) and exit (end). Find how many were present at the busiest moment.
- A person counts from start until end; at the exact end they are clocked out.
- The moments considered are the integers inside each shift.
PeakStaff(slots: list<Slot>) → int
C# needs a compiler and Drill does not host one yet, so this page is the reference rather than an exercise: the problem, worked examples, and the solution in full. To type it out, the same problem runs in Python.
Where you start
public int PeakStaff(List<Slot> slots) {
}Worked examples
| Call | Result |
|---|---|
PeakStaff(new List<Slot> { new Slot(0, 100), new Slot(50, 200), new Slot(60, 80) }) | 3 |
PeakStaff(new List<Slot> { new Slot(0, 100), new Slot(100, 200) }) | 1 |
PeakStaff(new List<Slot> { }) | 0 |
PeakStaff(new List<Slot> { new Slot(0, 10), new Slot(5, 15), new Slot(10, 20) }) | 2 |
Hint
Build a timeline of arrivals and departures, then sweep. Or sort all events.
Reference solution in C#
public int PeakStaff(List<Slot> slots) {
var events = new List<(int Time, int Delta)>();
foreach (var s in slots) { events.Add((s.Start, 1)); events.Add((s.End, -1)); }
events = events.OrderBy(e => e.Time).ThenBy(e => e.Delta).ToList();
int cur = 0, best = 0;
foreach (var ev in events) { cur += ev.Delta; best = Math.Max(best, cur); }
return best;
}