DepthFirstSearchEngine.java

package search.maze;

/**
 * 2D Maze Search: Performs a depth first search in a maze
 *
 * <p/>
 * Copyright 1998-2012 by Mark Watson. All rights reserved.
 * <p/>
 * This software is can be used under either of the following licenses:
 * <p/>
 * 1. LGPL v3<br/>
 * 2. Apache 2
 * <p/>
 */
public class DepthFirstSearchEngine extends AbstractSearchEngine {
    public DepthFirstSearchEngine(int width, int height) {
        super(width, height);
        iterateSearch(startLoc, 1);
    }

    private void iterateSearch(Location loc, int depth) {
        if (isSearching == false) return;
        maze.setValue(loc.x, loc.y, (short)depth);
        Location [] moves = getPossibleMoves(loc);
        for (int i=0; i<4; i++) {
            if (moves[i] == null) break; // out of possible moves from this location
            searchPath[depth] = moves[i];
            if (equals(moves[i], goalLoc)) {
                System.out.println("Found the goal at " + moves[i].x +
                                   ", " + moves[i].y);
                isSearching = false;
                maxDepth = depth;
                return;
            } else {
                iterateSearch(moves[i], depth + 1);
                if (isSearching == false) return;
            }
        }
        return;
    }
}