import heapq import itertools # ---------------- Priority Queue ---------------- class AdaptableHeapPriorityQueue: def __init__(self): self._heap = [] self._counter = itertools.count() def add(self, key, value): entry = [key, next(self._counter), value] heapq.heappush(self._heap, entry) return entry def update(self, entry, newkey, newvalue): entry[0] = newkey entry[2] = newvalue heapq.heapify(self._heap) def remove_min(self): while self._heap: key, _, value = heapq.heappop(self._heap) return key, value raise KeyError("Priority queue is empty") def is_empty(self): return len(self._heap) == 0 # ---------------- Graph Classes ---------------- class Vertex: def __init__(self, label): self.label = label def __hash__(self): return hash(self.label) def __str__(self): return str(self.label) class Edge: def __init__(self, u, v, w): self._u = u self._v = v self._w = w def opposite(self, x): return self._v if x == self._u else self._u def element(self): return self._w def endpoints(self): return (self._u, self._v) class Graph: def __init__(self): self._adj = {} def add_vertex(self, label): v = Vertex(label) self._adj[v] = [] return v def add_edge(self, u, v, w): e = Edge(u, v, w) self._adj[u].append(e) self._adj[v].append(e) def vertices(self): return self._adj.keys() def incident_edges(self, v): return self._adj[v] # ---------------- Prim-Jarník Algorithm ---------------- def MST_PrimJarnik(g): d = {} tree = [] pq = AdaptableHeapPriorityQueue() pqlocator = {} for v in g.vertices(): if len(d) == 0: d[v] = 0 else: d[v] = float('inf') pqlocator[v] = pq.add(d[v], (v, None)) while not pq.is_empty(): key, value = pq.remove_min() u, edge = value del pqlocator[u] if edge is not None: tree.append(edge) for link in g.incident_edges(u): v = link.opposite(u) if v in pqlocator: wgt = link.element() if wgt < d[v]: d[v] = wgt pq.update(pqlocator[v], d[v], (v, link)) return tree print("\Minimum Spanning Tree") print("\t---------------------------------") n = int(input("Enter number of vertices: ")) m = int(input("Enter number of edges: ")) g = Graph() vertices = [] for i in range(n+1): vertices.append(g.add_vertex(i)) print("Enter vertices of each edges and its weight as: u v weight") for _ in range(m): u, v, w = map(int, input().split()) g.add_edge(vertices[u], vertices[v], w) mst = MST_PrimJarnik(g) print("\nEdges in the Minimum Spanning Tree:") total = 0 for e in mst: u, v = e.endpoints() print(f"{u} -- {v} (weight = {e.element()})") total += e.element() print("Total weight of MST:", total)