深度优先搜索所遵循的搜索策略是尽可能“深”地搜索图。在深度优先搜索中，对于最新发现的结点，如果它还有以此为起点而未搜过的边，就沿着边继续搜索下 去。当结点v的所有边都已被探寻过，搜索将回溯到发现结点v有那条边的始结点。这一过程一直进行到已发现从源结点可达的所有结点为止。如果还存在未被发现 的结点，则选择其中一个作为源结点并重复以上过程，整个过程反复进行直到所有结点都被发现为止-Followed by depth-first search strategy is to search " Shenzhen"　to search for plans. In depth-first search for the newly discovered node, if it has not found this as a starting point over the edge, along the edge to continue the search indefinitely. When node v all edges have been searching for, the search will go back to the node v has found that the only edge nodes. This process has been carried out to have been found up from the source node until all nodes. If there are still undiscovered node, then choose one node as the source and repeat the above process, the whole process repeated until all nodes have been found so far