add new solutions

solutions/24/q2402/solution.go

@@ -0,0 +1,77 @@
+package q2402
+
+import (
+	"container/heap"
+	"slices"
+)
+
+type Room struct {
+	id           int
+	meetingStart int
+	meetingEnd   int
+}
+
+type Rooms []Room
+
+func (r *Rooms) Len() int          { return len(*r) }
+func (r *Rooms) Push(x any)        { (*r) = append((*r), x.(Room)) }
+func (r *Rooms) Swap(i int, j int) { (*r)[i], (*r)[j] = (*r)[j], (*r)[i] }
+
+func (r *Rooms) Less(i int, j int) bool {
+	if (*r)[i].meetingEnd == (*r)[j].meetingEnd {
+		return (*r)[i].id < (*r)[j].id
+	}
+	return (*r)[i].meetingEnd < (*r)[j].meetingEnd
+}
+
+func (r *Rooms) Pop() any {
+	last := len(*r) - 1
+	ret := (*r)[last]
+	*r = (*r)[:last]
+	return ret
+}
+
+func mostBooked(n int, meetings [][]int) int {
+	timesBooked := make([]int, n)
+	empty := make(Rooms, n)
+	for i := range empty {
+		empty[i] = Room{id: i}
+	}
+	inUse := make(Rooms, 0, n)
+
+	slices.SortFunc(meetings, func(a, b []int) int { return a[0] - b[0] })
+	for i := range meetings {
+		start, end := meetings[i][0], meetings[i][1]
+		for len(inUse) > 0 && inUse[0].meetingEnd <= start {
+			heap.Push(&empty, Room{id: inUse[0].id})
+			heap.Pop(&inUse)
+		}
+
+		if len(empty) > 0 {
+			id := empty[0].id
+			timesBooked[id]++
+			heap.Push(&inUse, Room{
+				id:           id,
+				meetingStart: start,
+				meetingEnd:   end,
+			})
+			heap.Pop(&empty)
+		} else {
+			room := &inUse[0]
+			timesBooked[room.id]++
+			room.meetingStart, room.meetingEnd = room.meetingEnd, end-start+room.meetingEnd
+			heap.Fix(&inUse, 0)
+		}
+	}
+
+	mb, mbIdx := timesBooked[0], 0
+	for i := 1; i < len(timesBooked); i++ {
+		if timesBooked[i] > mb {
+			mb, mbIdx = timesBooked[i], i
+		}
+	}
+	return mbIdx
+}
+
+var _ heap.Interface = &Rooms{}
+var _ = mostBooked