CS347 SP2005 The Plank Puzzle: Phase IV - A* Graph Search

Assignment

"Your challenge is to find a route across a crocodile infested swamp using just a handful of rather short planks. Fortunately the planks are light enough to move around, and the swamp is full of old tree-stumps which will support the planks to form temporary bridges. So by careful planning, and re-use of planks, you might just find a route. Needless to say you can only move planks you can physically reach, so try not to leave any too far behind. The best way to understand the plank puzzle concept is to imagine yourself stuck in a real swamp, with tree-stumps too far apart to jump-between, and planks too heavy to move more than one at a time. The remaining rules get a bit fiddley, but here they all are:
• You can pick up and carry a plank provided you have access to one end.
• You can only pick-up and carry one plank at a time.
• Planks must be supported both ends, and must be an exact fit.
• You cannot jump between stumps or planks.
• You cannot move a plank if you are already carrying one.
• Planks cannot be used diagonally, only north-south or east-west.
• Planks cannot support other planks, and cannot be stacked.
• Planks cannot bridge intermediate stumps or planks.
The objective is to find a path from start (home icon in class framework) to finish (diamond icon in class framework) with lower cost paths being more desirable (the optimal path is the one with the lowest path cost)."

In this fourth phase all you have to do is modify the CAsPlayer class (asplayer.cpp) in the provided Qt framework to attempt to solve the puzzle using A* Graph Search. Note that when the play function is first called it needs to generate a complete solution and return the first move; in subsequent calls it should return the corresponding subsequent moves without regenerating the solution! Also note that when the reset function is called, it should reset the play function so that the next call to play will regenerate the complete solution. The minimal requirement for the heuristic function is to somehow use knowledge about the current board configuration; note that a somewhat intelligent approach is required to earn all the heuristic points; further note that sophisticated heuristic functions will be rewarded with up to 20 bonus points. See http://web.umr.edu/~cs347a/sp2005/planks for framework instructions.

Note: this is an individual project; plagiarism of any type will result in a zero grade.

You need to submit only iddfgsplayer.cpp and, if you have modified it, iddfgsplayer.h on or before Saturday 2/19/2005. This is accomplished by following the instructions at http://web.umr.edu/~tauritzd/submission.html.

Grading

• A* Graph Search implementation: 70
• Heuristic: 10 (plus up to 20 bonus points for more sophisticated heuristic functions)
• Good programming practices (style, comments, modular design, etc.): 10
• Code reliability (no crashes, defensive programming, compiles correctly): 10

Multiple Submissions and Late Submissions

While it is hoped that all code will be submitted error-free and on time, this may not always be the case, so the following rules apply if code is not submitted error-free or on time:

• You must make your final submission within 48 hours of the due date. Submissions which are more than two days late will not be graded.
• If your code is submitted late, a 10 point per day penalty will apply (fractions of days are rounded up), after two days you will automatically receive a zero.
• Resubmissions are allowed but late penalties will apply based on the last submission.