From 5f2a715ebd68fcb47705d01b14a75ca353ced001 Mon Sep 17 00:00:00 2001
From: Matej Focko <me@mfocko.xyz>
Date: Fri, 9 Aug 2024 00:17:56 +0200
Subject: [PATCH] =?UTF-8?q?go:=20add=20=C2=AB841.=20Keys=20and=20Rooms?=
 =?UTF-8?q?=C2=BB?=
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Signed-off-by: Matej Focko <me@mfocko.xyz>
---
 go/keys-and-rooms.go | 48 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 go/keys-and-rooms.go

diff --git a/go/keys-and-rooms.go b/go/keys-and-rooms.go
new file mode 100644
index 0000000..4a673d1
--- /dev/null
+++ b/go/keys-and-rooms.go
@@ -0,0 +1,48 @@
+package main
+
+import (
+	arraystack "github.com/emirpasic/gods/v2/stacks/arraystack"
+)
+
+type DFSEntry struct {
+	room  int
+	index int
+}
+
+func (e *DFSEntry) Next() DFSEntry {
+	return DFSEntry{room: e.room, index: e.index + 1}
+}
+
+func canVisitAllRooms(rooms [][]int) bool {
+	s := arraystack.New[DFSEntry]()
+	s.Push(DFSEntry{room: 0, index: 0})
+
+	visited := make([]bool, len(rooms))
+	visited[0] = true
+
+	for !s.Empty() {
+		key, _ := s.Pop()
+
+		if key.index >= len(rooms[key.room]) {
+			continue
+		}
+
+		s.Push(key.Next())
+
+		unlockedRoom := rooms[key.room][key.index]
+		if visited[unlockedRoom] {
+			continue
+		}
+
+		visited[unlockedRoom] = true
+		s.Push(DFSEntry{room: unlockedRoom, index: 0})
+	}
+
+	for _, unlocked := range visited {
+		if !unlocked {
+			return false
+		}
+	}
+
+	return true
+}