![]() ![]() This method performs the recursive search. We do this simply by calling the public method solve(). Once all the abstract methods have been overridden, we are ready to use our derived class to seek a solution. It must be realized by a class (in our example, the Move class) holding all the information needed to represent a game's move. The class Step is just an empty interface. One has to override this method in order to save the solution's step. When a solution is found, the algorithm calls saveStep() for every step of the solution. The solved() method must be overridden in order to tell if the current configuration of the game is a solution (returns true) or not (returns false). The next two methods, doStep() and undoStep() is where we update the game's state (in our example, where we change the position of the pieces on the board): doStep() must perform the step indicated by its parameter, while undoStep() must roll the game back to the previous state, undoing the specified step. Note that these methods are declared const, in that they don't have to modify the state of the game: firstStep() returns a pointer to an object of class Step, and nextStep() modifies its argument. We accomplish this task by implementing the first two methods listed above, firstStep() and nextStep(). We must be able to specify the possible steps (or moves) that can be made at a given state of the game. In the Solitaire puzzle, for example, a step consists of a move of a piece on the board, according to the game's rules. We know that backtracking applies to problems that can be solved by performing a sequence of steps. the current disposition of the pieces on the board. In our example, the Backtrack class is realized by the Solitaire class, which represents the game board and keeps track of the game state, i.e. Virtual void saveStep( const Step *pc_step, Virtual void undoStep( const Step *pc_step) = 0 Virtual void doStep( const Step *pc_step) = 0 Virtual bool nextStep(Step *p_step) const = 0 To use this class, you have to derive your own class from it and implement the following abstract methods: It was written mainly for teaching purposes in order to take the backtracking logic out of the details of a particular problem. The Backtrack class is an extremely general implementation of the DFS (Depth First Search) backtracking algorithm. The source code comprises of the template class Stack, a simple MFC based typed stack. It also provides an object oriented vestment to backtracking, in the form of a reusable class holding all the backtracking logic. The main purpose of this program is to illustrate the concepts of recursive function, inherently recursive problem and backtracking. The program, in fact, implements a simple backtracking algorithm to search for a solution starting from the current disposition of the pieces on the board. the program can solve the puzzle in your place - or at least it tries to.Pseudo code alone is enough to put me on the right track.This program lets you play Solitaire puzzle (also known as Peg Solitaire Puzzle) with two big advantages over a real gaming table: I'm coding in Java, but since this is a bit vague I'm only expecting pseudo code answers. Changing my jump() function could potentially affect my heuristic. This is for a school project so I have to implement an uninformed search and a heuristic search algorithm. ![]() I would have to change it to take the start and end position desired for each jump, which is easy enough to change, but I don't know if its better or worse for the algorithm. Is recursion a good method to solve this puzzle? My jump function currently works by only asking for the position you would want to jump to. Between backtracking and updating the current peg I'm lost.ĭoes all of this sound too complicated? Should I just remove the moves and sCpeg() options and have the search algorithm randomly jump until a solution is found? When I was writing this idea out it sounds like a perfect example to use recursion on except I don't know how to properly use recursion in this scenario. If a solution is not found backtrack, update the current peg and repeat the process. It's done as a very basic heuristic for what I hope to be a search algorithm: Explore all the possible jumps available with one peg. Every time you change the current peg and use it to jump that counts as a move. I connected this to a moves variable for the purpose of solving it. In my code for the game board object I have a function sCpeg(int a, int b) which changes the peg you are currently using to jump. You take one peg and jump it over another into an empty hole and the goal is to have only one peg left. Everyone knows of the cracker barrel triangle peg solitaire game. ![]()
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