/** executes the algorithm */
public String execute() {
// have we found the solution?
boolean solution = false;
// start the timer
long startTime = System.currentTimeMillis();
// initial town
toExpand.add(new Town(sourceCity, 0, 0, 0));
while (!toExpand.isEmpty() && !solution) {
// gets the city with lower g value
Town currentTown = toExpand.poll();
nodes++;
// rebuild the followed route for the selected town
Town aux = currentTown;
followedRoute = new ArrayList();
followedRoute.add(aux.number);
while (aux.level != 0) {
aux = aux.parent;
followedRoute.add(0, aux.number);
}
if (currentTown.level == distances.getCitiesCount()) {
solution = true;
optimumRoute = followedRoute;
optimumCost = currentTown.g;
} else {
for (int i = 0; i < distances.getCitiesCount(); i++) {
// have we visited this city in the current followed route?
boolean visited = followedRoute.contains(i);
boolean isSolution =
(followedRoute.size() == distances.getCitiesCount()) && (i == sourceCity);
if (!visited || isSolution) {
Town childTown =
new Town(
i,
currentTown.g + distances.getCost(currentTown.number, i),
0,
currentTown.level + 1);
childTown.parent = currentTown;
toExpand.add(childTown);
}
}
}
}
long endTime = System.currentTimeMillis();
result = "-------------------------------------\n";
result += "BÚSQUEDA DE COSTO UNIFORME:\n";
result += "-------------------------------------\n";
result += "MEJOR SOLUCIÓN: \t" + optimumRoute.toString() + "\nCOSTE: \t\t" + optimumCost + "\n";
result += "NODOS VISITADOS: \t" + nodes + "\n";
result += "TIEMPO TRANSCURRIDO: \t" + (endTime - startTime) + " ms\n";
result += "-------------------------------------\n";
return result;
}
