Added Kruskal's Algorithm in graph folder code in python

Author: Smriti-Prajapati

TheAlgorithm/Kruskal_Algorithm.py

@@ -0,0 +1,79 @@
+graph folder structure:
+graph/
+__init__.py
+graph.py
+kruskal.py
+
+graph.py:
+class Graph:
+    def __init__(self, vertices):
+        self.V = vertices
+        self.graph = []
+
+    def addEdge(self, u, v, w):
+        self.graph.append([u, v, w])
+
+kruskal.py:
+from .graph import Graph
+
+class Kruskal:
+    def __init__(self, graph):
+        self.graph = graph
+
+    def find(self, parent, i):
+        if parent[i] != i:
+            parent[i] = self.find(parent, parent[i])
+        return parent[i]
+
+    def union(self, parent, rank, x, y):
+        if rank[x] < rank[y]:
+            parent[x] = y
+        elif rank[x] > rank[y]:
+            parent[y] = x
+        else:
+            parent[y] = x
+            rank[x] += 1
+
+    def KruskalMST(self):
+        result = []
+        i, e = 0, 0
+        self.graph.graph = sorted(self.graph.graph, key=lambda item: item[2])
+        parent = []
+        rank = []
+
+        for node in range(self.graph.V):
+            parent.append(node)
+            rank.append(0)
+
+        while e < self.graph.V - 1:
+            u, v, w = self.graph.graph[i]
+            i = i + 1
+            x = self.find(parent, u)
+            y = self.find(parent, v)
+
+            if x != y:
+                e = e + 1
+                result.append([u, v, w])
+                self.union(parent, rank, x, y)
+
+        minimumCost = 0
+        print("Edges in the constructed MST")
+        for u, v, weight in result:
+            minimumCost += weight
+            print("%d -- %d == %d" % (u, v, weight))
+        print("Minimum Spanning Tree", minimumCost)
+
+Usage:
+from graph import Graph
+from graph.kruskal import Kruskal
+
+if __name__ == '__main__':
+    g = Graph(4)
+    g.addEdge(0, 1, 10)
+    g.addEdge(0, 2, 6)
+    g.addEdge(0, 3, 5)
+    g.addEdge(1, 3, 15)
+    g.addEdge(2, 3, 4)
+
+    k = Kruskal(g)
+    k.KruskalMST()