DFS 기본 코드

def dfs(graph, idx, visited):
	visited[idx]=True
    for i in graph[idx]:
    	if not visited[i]:
        	dfs(graph,i,visited)

graph = [[],
		[2,3,8],
        [1,7],
        ...]

visited = [False]*(len(graph))

# dfs 시작
dfs(graph, 1,visited)