package main

import "fmt"

func main() {
	res := canVisitAllRooms([][]int{{1}, {2}, {}})
	fmt.Printf("%+v\n", res)
}

func canVisitAllRooms(rooms [][]int) bool {
	if len(rooms) > 0 && len(rooms[0]) == 0 {
			return false
	}

	keys := getAllKeys(0, make(map[int]struct{}), rooms)
	keys[0] = struct{}{}    

	for i := 0; i < len(rooms); i++ {
			if _, ok := keys[i]; !ok {
					return false
			}
	}
	return true
}

func getAllKeys(index int, seen map[int]struct{}, rooms [][]int) map[int]struct{} {
	keys := map[int]struct{}{}

	for j := 0; j < len(rooms[index]); j++ {
			if _, ok := keys[rooms[index][j]]; ok {
					continue
			}
			keys[rooms[index][j]] = struct{}{}
			insideKeys := getAllKeys(j, keys, rooms)
			for k := range insideKeys {
					keys[k] = struct{}{}
			}
	}
	
	return keys
}