Create prims_minimum_spanning.py

code implemented for Prim's Algorithm to find minimum spanning tree. Although there was file named minimum_spanning_tree.py in graph section but contain only Kruskal Algorithm . Prim's Algo. was still missing

Author: Himanshu-77

algorithms/graph/prims_minimum_spanning.py

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+import heapq  # for priority queue
+
+# input number of nodes and edges in graph
+n, e = map (int,input().split())
+
+# initializing empty graph as a dictionary (of the form {int:list})
+g = dict (zip ([i for i in range(1,n+1)],[[] for i in range(n)]))
+
+# input graph data
+for i in range(e):
+    a, b, c = map (int,input().split())
+    g[a].append([c,b])
+    g[b].append([c,a])
+    
+vis = []
+s = [[0,1]]
+prim = []
+mincost = 0
+
+# prim's algo. to find weight of minimum spanning tree
+while (len(s)>0):
+    v = heapq.heappop(s)
+    x = v[1]
+    if (x in vis):
+        continue
+
+    mincost += v[0]
+    prim.append(x)
+    vis.append(x)
+
+    for j in g[x]:
+        i = j[-1]
+        if(i not in vis):
+            heapq.heappush(s,j)
+
+print(mincost)