Figure 2 shows a search tree with 21 nodes. Please uses
Depth First Search algorithms showing in Figures 4 and 5 to report
the order of the nodes being visited, and the Fringe structure of
each method (report fringe structure of each step as show in the
table below). Please compare the fringe structure and explain the
memory consumption of each method, with respect to branching factor
(b) and the search depth (d).