Flutter, Flutter App Development, Data Structures, Algorithms.
charlie]); bob.friends.addAll([alice, david]); charlie.friends.addAll([alice, david, erin]); david.friends.addAll([bob, charlie]); erin.friends.addAll([charlie]); class FriendsGraph { final Map<int, User> users; FriendsGraph({required this.users}); bool areFriends(int userId1, int userId2) { final