#깊이 우선 탐색 dfs

#	제목	푼 사람 수	평균 시도
6451	Alien Security	5	4.60
6561	Decode the Tree	2	9.50
6584	The Settlers of Catan	22	1.73
6649	Tree Insertions	5	1.40
6659	All Friends	2	5.00
6743	Rectangle Cutting	9	1.00
6747	Median Weight Bead	19	1.53
6753	Chances of winning	18	1.22
6755	Who is taller?	48	2.17
6759	LHC	7	1.29
6772	Choose Your Own Arithmetic	14	3.93
6832	Maze	56	2.05
6837	Herding	15	1.80
6847	Friends	22	1.59
6879	Pyramid Message Scheme	3	1.67
6881	Number Matrix	62	2.89
6907	Floor Plan	31	3.29
6945	Surfing	2	11.50
6948	Subsets	18	1.72
6984	All Roads Lead Where?	40	1.30
7088	Word counting	8	1.63
7139	Toll	39	2.36
7149	Can of Worms	29	3.07
7166	Värvipalett	1	10.00
7191	Turning a Tree	4	2.75
7198	Tähekabe	4	2.00
7228	Melagiai	8	1.00
7234	Unter	2	4.50
7299	Food Cubes	26	2.15
7352	Sorting It All Out	12	1.75
7535	A Bug’s Life	203	2.06
7644	Highway Construction	22	2.73
7669	Go	27	1.15
7812	중앙 트리	535	2.85
7827	Transitive Closure	64	2.05
7858	Tetris Alphabet	7	2.43
7919	Strażak	1	9.00
7993	후르츠 치킨	26	5.85
8063	Three-Coloring of Binary Trees	9	1.33
8075	Word Equations	7	6.29
8110	Trees	12	2.08
8119	Polygon	14	2.07
8121	Step Traversing a Tree	34	1.65
8128	Subway	45	6.42
8142	Ridges and Valleys	50	1.84
8184	Guilds	45	2.31
8233	Minimalist Security	20	6.15
8265	Plecak	3	2.00
8314	Acyclic Decomposition	52	3.35
8340	Colouring	20	1.15

123456781117