Graphs and trees provide you with ways to visualize data sets, and the opportunity to do analysis on the data (e.g., shortest path). Knowing the structure of a database enables you to choose a proper algorithm for searching for data within a database.
Part I
Trees are somewhat less complicated than graphs, which makes things like data searching easier, when a data has the structure of a tree. However, not all data can be represented by a tree. Describe an example of a data set that cannot be represented by a tree, but that be represented by a more general graph. Explain why it cannot be represented by a tree.
Part II
The set of all possible sequences of moves in a chess game can be represented by a tree (decision tree). If you were to write a chess-playing computer program that can determine the best move at each step by searching the tree of possible moves and outcomes, would you use a depth-first or a breadth-first search for the best move at each step in the game? Explain.