Exemplo n.º 1
0
class LazyPrimMST:
    def __init__(self, g):
        self.pq = MinPQ()
        self.marked = []
        self.mst = Queue()

        for i in range(g.v):
            self.marked.append(False)
        self.visit(g, 0)
        while not self.pq.is_empty():
            e = self.pq.del_min()
            v = e.either()
            w = e.other(v)
            if self.marked[v] and self.marked[w]:
                continue
            self.mst.enqueue(e)
            if not self.marked[v]:
                self.visit(g, v)
            if not self.marked[w]:
                self.visit(g, w)

    def visit(self, g, v):
        self.marked[v] = True
        for e in g.adj[v]:
            if not self.marked[e.other(v)]:
                self.pq.insert(e)
Exemplo n.º 2
0
class KruskalMST:
    def __init__(self, g):
        self.mst = Queue()
        self.pq = MinPQ()
        self.uf = UF(g.v)

        for e in g.edges:
            self.pq.insert(e)

        while not self.pq.is_empty() and self.mst.size() < g.v - 1:
            e = self.pq.del_min()
            v = e.either()
            w = e.other(v)
            if self.uf.connected(v, w):
                continue
            self.mst.enqueue(e)
            self.uf.union(v, w)