Added Prim’s minimum spanning tree algorithm #8

Prims_Algorithm.py

@@ -0,0 +1,51 @@
+from dataclasses import dataclass, field
+@dataclass(eq=False)
+class Node :
+    idnum : int
+@dataclass
+class Graph :
+    source  : int
+    adjlist : dict
+    def PrimsMST(self):
+        priority_queue = { Node(self.source) : 0 }
+        added = [False] * len(self.adjlist)
+        min_span_tree_cost = 0
+        while priority_queue :
+            node = min(priority_queue, key=priority_queue.get)
+            cost = priority_queue[node]
+            del priority_queue[node]
+            if added[node.idnum] == False :
+                min_span_tree_cost += cost
+                added[node.idnum] = True
+                print("Node added: " + str(node.idnum) + ",cost: "+str(min_span_tree_cost))
+                for item in self.adjlist[node.idnum] :
+                    adjnode = item[0]
+                    adjcost = item[1]
+                    if added[adjnode] == False :
+                        priority_queue[Node(adjnode)] = adjcost
+        return min_span_tree_cost
+def main() :
+    g1_edges_from_node = {}
+    g1_edges_from_node[0] = [ (1,1), (2,2), (3,1), (4,1), (5,2), (6,1) ]
+    g1_edges_from_node[1] = [ (0,1), (2,2), (6,2) ]
+    g1_edges_from_node[2] = [ (0,2), (1,2), (3,1) ]
+    g1_edges_from_node[3] = [ (0,1), (2,1), (4,2) ]
+    g1_edges_from_node[4] = [ (0,1), (3,2), (5,2) ]
+    g1_edges_from_node[5] = [ (0,2), (4,2), (6,1) ]
+    g1_edges_from_node[6] = [ (0,1), (2,2), (5,1) ]
+
+    g1 = Graph(0, g1_edges_from_node)
+    cost = g1.PrimsMST()
+    print("Cost of the minimum spanning tree in graph 1 : " + str(cost) +"\n")
+    g2_edges_from_node = {}
+    g2_edges_from_node[0] = [ (1,4), (2,1), (3,5) ];
+    g2_edges_from_node[1] = [ (0,4), (3,2), (4,3), (5,3) ];
+    g2_edges_from_node[2] = [ (0,1), (3,2), (4,8) ];
+    g2_edges_from_node[3] = [ (0,5), (1,2), (2,2), (4,1) ];
+    g2_edges_from_node[4] = [ (1,3), (2,8), (3,1), (5,3) ];
+    g2_edges_from_node[5] = [ (1,3), (4,3) ];
+    g2 = Graph(0, g2_edges_from_node)
+    cost = g2.PrimsMST()
+    print("Cost of the minimum spanning tree in graph 1 : " + str(cost))
+if __name__ == "__main__" :
+    main()