private Queue<SearchNode> GetSolution(Board initial) {
Queue<SearchNode> queue = new Queue<SearchNode>();
MinPQ<SearchNode> pq = new MinPQ<SearchNode>();
SearchNode node = new SearchNode();
node.brd = initial;
node.moves = 0;
// node.priority = initial.manhattan();
node.prev = null;
pq.insert(node);
SearchNode curNode = null;
while (!pq.isEmpty()) {
curNode = pq.delMin();
if (curNode.brd.isGoal()) break;
Iterable<Board> qe = curNode.brd.neighbors();
Iterator it = qe.iterator();
while (it.hasNext()) {
node.brd = (Board) it.next();
node.moves = curNode.moves + 1;
node.prev = curNode;
// node.priority = node.brd.manhattan();
queue.enqueue(node);
}
}
if (queue.isEmpty()) return null;
else {
do {
queue.enqueue(curNode);
curNode = curNode.prev;
} while (curNode != null);
return queue;
}
}
/** Unit tests the <tt>MinPQ</tt> data type. */
public static void main(String[] args) {
MinPQ<String> pq = new MinPQ<String>();
while (!StdIn.isEmpty()) {
String item = StdIn.readString();
if (!item.equals("-")) pq.insert(item);
else if (!pq.isEmpty()) StdOut.print(pq.delMin() + " ");
}
StdOut.println("(" + pq.size() + " left on pq)");
}
KruskalMST(EdgeWeightedGraph G) {
MinPQ<Edge> pq = new MinPQ<Edge>(); // we dont need to pass a new comparator let it
// follow the natural ordering of edges
double temp_wt = 0;
for (Edge e : G.edges()) pq.insert(e);
UF set = new UF(G.V());
while (!pq.isEmpty() && mst.size() < (G.V() - 1)) {
Edge e = pq.delMin();
int v = e.either();
int w = e.other(v);
if (!set.connected(v, w)) {
set.union(v, w);
mst.add(e);
temp_wt += e.weight();
}
}
this.weight = temp_wt;
}
// Kruskal's algorithm
public KruskalMST(EdgeWeightedGraph G) {
// more efficient to build heap by passing array of edges
MinPQ<Edge> pq = new MinPQ<Edge>();
for (Edge e : G.edges()) {
pq.insert(e);
}
// run greedy algorithm
UF uf = new UF(G.V());
while (!pq.isEmpty() && mst.size() < G.V() - 1) {
Edge e = pq.delMin();
int v = e.either();
int w = e.other(v);
if (!uf.connected(v, w)) { // v-w does not create a cycle
uf.union(v, w); // merge v and w components
mst.enqueue(e); // add edge e to mst
weight += e.weight();
}
}
// check optimality conditions
assert check(G);
}
public LazyPrimMST(EdgeWeightedGraph G) {
pq = new MinPQ<Edge>();
marked = new boolean[G.V()];
mst = new Queue<Edge>();
visit(G, 0); // assumes G is connected (see ex. 4.3.22)
while (!pq.isEmpty()) {
Edge e = pq.delMin(); // Get lowest-weight from pq.
int v = e.either();
int w = e.other(v);
if (marked[v] && marked[w]) {
continue; // Skip if ineligible
}
mst.enqueue(e); // Add edge to tree
if (!marked[v]) { // Add vertex to tree (either v or w).
visit(G, v);
}
if (!marked[w]) {
visit(G, w);
}
}
}
/**
* Dado un grafo no dirigido y con pesos, ejecuta el algoritmo de Kruskal para la obtención del su
* árbol de cobertura mínima.
*
* @param G Grafo no dirigido con pesos al cual se le deesea obtener su arbol de cobertura mínima.
*/
public void minimumSpanningTree(EdgeWeightedGraph G) // By Kruskal's algorithm
{
LinkedList<Edge> mst = new LinkedList<>();
MinPQ<Edge> pq = new MinPQ<>(G.E());
for (Edge edge : G.edges()) // Bag<Edge> != Comparator<Edge> :c
pq.insert(edge);
UF uf = new UF(G.V());
while (!pq.isEmpty() && mst.size() < G.V() - 1) {
Edge edge = pq.delMin();
int v = edge.either(), w = edge.other(v);
if (!uf.connected(v, w)) {
uf.union(v, w);
mst.add(edge);
}
}
System.out.println("");
for (Edge edge : mst) System.out.println(edge);
}
private void solveInternal(MinPQ<SearchNode> queue, boolean twin) {
while (!queue.isEmpty() && solvable == null) {
// StdOut.println("Queue size = "+queue.size());
SearchNode min = queue.delMin();
// StdOut.println("Manhatan + moves = "+(min.board.manhattan()+min.moves));
if (min.board.isGoal()) {
if (twin) {
solvable = false;
} else {
solution = min;
solvable = true;
}
return;
} else {
for (Board n : min.board.neighbors()) {
if (min.previous == null || (!n.equals(min.previous.board))) {
queue.insert(new SearchNode(n, min, min.moves + 1));
}
}
}
}
}
public boolean hasNext() {
return !copy.isEmpty();
}
public boolean isEmpty() {
return min.isEmpty() && max.isEmpty();
}