CSE 473 Practice Problems (this is only a practice, this is not a test)

 

True or False:

 

Depth first search is a complete search strategy.

 

DFID guaranteed to find the shortest path to a goal node.

 

DFID is guaranteed to terminate (assume that a goal node exists).

 

DFID is just as fast as depth-first search.

 

DFID requires less memory than best-first search.

 

The PageGather algorithm is an example of unsupervised learning.

 

The version space algorithm is guaranteed to terminate given enough examples and a finite hypothesis space.

 

 

(4 points) Draw a game tree where the conspiracy number required to change the mini-max value at the root from 4 to 6 is 2.

 

When is a search procedure said to be {\em admissible}?  Give an example of an admissible search procedure.

 

 

Game-playing search (14 points)

 

 Consider the following game tree.  Assume it’s the maximizing player's

turn.  Assume that $\alpha$/$\beta$ pruning of the search tree is used.

The labels on the leaf nodes are the static evaluations of each state.

 

 

 

 

 

 

 

 

 

 

 

max                                     A

 

min                  B                  C                      D

 

max             E       F       G       H      I          J         K

 

            L    M    N   O   P   Q   R   S   T   U   V   W   X    Y  Z

            4    8     9   3   2   -2   9  -1    8   4   3     6   5    7   1

 

 

 

 (3 points)

Prominently label the nodes in the tree with their minimax values.

 

 (1 points) Which move (ie, which node) would be selected by Max?

 

 

 (3 points) List the nodes that the $\alpha$/$\beta$ procedure would prune away:

 

 

 Suppose that we traverse the game tree from right to left, instead of from left to right.  Is it possible that this will result in a change to:

 

 

 The minimax value at the root?

 The number of nodes pruned?

 

Suppose POP adds the step puton(a ?X) to its plan, and that step threatens the causal link puton(e d)-clear(b)--$>$puton(c b). State precisely {\em all} the constraints POP could post to resolve this threat.

 

 

 

 

 

 

 

 

 

 

 

 

 

What algorithm, heuristic or search strategy would you use to most effectively solve the following problems:

(be as specific and precise as you can be)

 

The shortest path between two points in N-dimensional space

 

The Horizon effect

 

Map coloring

 

Learning a concept whose description is some short Boolean formula

 

Learning a concept in the presence of noise where the learned hypothesis have to be examined by a person before they are accepted

 

Assigning classes to rooms at UW based on enrollments, room sizes, and course meeting times.