Add problem description to go code

src/l33tcode/841.go

@@ -1,10 +1,31 @@
+/*
+Keys and Rooms
+
+Instructions:
+There are n rooms labeled from 0 to n - 1 and all the rooms are locked except for room 0. Your goal is to visit all the rooms. However, you cannot enter a locked room without having its key.
+
+When you visit a room, you may find a set of distinct keys in it. Each key has a number on it, denoting which room it unlocks, and you can take all of them with you to unlock the other rooms.
+
+Given an array rooms where rooms[i] is the set of keys that you can obtain if you visited room i, return true if you can visit all the rooms, or false otherwise.
+
+Constraints:
+n == rooms.length
+2 <= n <= 1000
+0 <= rooms[i].length <= 1000
+1 <= sum(rooms[i].length) <= 3000
+0 <= rooms[i][j] < n
+All the values of rooms[i] are unique.
+*/
 package main
 
 import "fmt"
 
 func main() {
-	res := canVisitAllRooms([][]int{{1, 3}, {3, 0, 1}, {2}, {0}})
+	res := canVisitAllRooms([][]int{{1}, {2}, {3}, {}})
-	fmt.Printf("%+v\n", res)
+	fmt.Printf("Example 1 works: %+v\n\n", res)
+
+	res = canVisitAllRooms([][]int{{1, 3}, {3, 0, 1}, {2}, {0}})
+	fmt.Printf("Example 2 works: %+v\n", res)
 }
 
 func canVisitAllRooms(rooms [][]int) bool {