/** @return node that contains the path traveled from start to finish */
protected Node mazeSearch() {
Node currNode = this.pq.remove();
// found solution if current node is the on FIN
if (this.solution[currNode.getX()][currNode.getY()] == FIN) {
return currNode;
}
exploreMoves(currNode);
return mazeSearch();
}
/**
* explore the neighbor nodes and add them to the queue if they have not been explored
*
* @param currNode
*/
protected void exploreMoves(Node currNode) {
int x = currNode.getX();
int y = currNode.getY();
// Add all adjacent nodes that are not WALLS to the list
// Left
boolean l = checkAndAddNodeToList(currNode, x - 1, y);
// Up
boolean u = checkAndAddNodeToList(currNode, x, y - 1);
// Right
boolean r = checkAndAddNodeToList(currNode, x + 1, y);
// Down
boolean d = checkAndAddNodeToList(currNode, x, y + 1);
}
/** execute algorithm and create the solution maze matrix */
public void search() {
findStartFin();
this.totalCost = 0;
this.expands = 0;
Node solNode = mazeSearch();
this.solNode = solNode;
this.expands -= this.pq.size();
// backtrack from fin to start
while (solNode.getParent() != null) {
int x = solNode.getX();
int y = solNode.getY();
this.solution[x][y] = FIN; // MARK THE SOLUTION PATH WITH THE START SYMBOL
solNode = solNode.getParent();
this.totalCost++;
debugSolution(solNode);
}
}
/**
* create a new node and add queue if the new node cost is less than the current cost
*
* @param currNode
* @param x
* @param y
*/
protected boolean checkAndAddNodeToList(Node currNode, int x, int y) {
int cost = currNode.getCurrentPathCost() + 1;
int h = 0; // heuristic(x,y);
if (h + cost < this.maze[x][y]) {
this.pq.add(new Node(currNode, x, y, cost, h));
this.maze[x][y] = h + cost;
this.expands++;
return true;
}
return false;
}