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
}