go: add «2127. Maximum Employees to Be Invited to a Meeting»

URL:	https://leetcode.com/problems/maximum-employees-to-be-invited-to-a-meeting/
Signed-off-by: Matej Focko <me@mfocko.xyz>

go/maximum-employees-to-be-invited-to-a-meeting.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	aq "github.com/emirpasic/gods/v2/queues/arrayqueue"
+)
+
+func maximumInvitations(favorite []int) int {
+	n := len(favorite)
+
+	inDegrees := make([]int, n)
+	for _, fav := range favorite {
+		inDegrees[fav]++
+	}
+
+	q := aq.New[int]()
+	for p, favored := range inDegrees {
+		if favored == 0 {
+			q.Enqueue(p)
+		}
+	}
+
+	depth := make([]int, n)
+	for i, _ := range depth {
+		depth[i] = 1
+	}
+
+	for person, ok := q.Dequeue(); ok; person, ok = q.Dequeue() {
+		next := favorite[person]
+		depth[next] = max(depth[next], depth[person]+1)
+
+		inDegrees[next]--
+		if inDegrees[next] == 0 {
+			q.Enqueue(next)
+		}
+	}
+
+	longestLoop := 0
+	doubleLoop := 0
+
+	for p0, degree := range inDegrees {
+		if degree == 0 {
+			continue
+		}
+
+		loopLength := 0
+		for p := p0; inDegrees[p] != 0; p = favorite[p] {
+			inDegrees[p] = 0
+			loopLength++
+		}
+
+		if loopLength == 2 {
+			doubleLoop += depth[p0] + depth[favorite[p0]]
+		} else {
+			longestLoop = max(longestLoop, loopLength)
+		}
+	}
+
+	return max(longestLoop, doubleLoop)
+}