DFS 深度优先遍历

public static void visit(HashMap<Character,LinkedList<Character>> graph,HashMap<Character,Boolean> visited,char start){if(!visited.containsKey(start)){System.out.println("开始访问节点"+start);visited.put(start, true);LinkedList<Character> list=graph.get(start);System.out.println(list.size());for(int i=0;i<list.size();i++){if(!visited.containsKey(list.get(i))){visit(graph,visited,list.get(i));}}System.err.println("退出节点"+start);}}