Prims Algorithm

Kruskals Algorithm

@@ -0,0 +1,53 @@
+
+
+class Edge:
+    def __init__(self):
+        self.src = 0
+        self.dest = 0
+        self.weight = 0
+
+
+def findParent(src, parent):
+    if parent[src] == 0:
+        return src
+    return findParent(parent[src], parent)
+
+
+def kruskals(edges, n, e):
+    edges.sort(key=lambda edge: edge.weight)
+    edge = Edge()
+    output = [edge] * (n - 1)  # n-1 edges
+    parent = [0] * (n)
+
+    count = 0
+    i = 0
+    while count != (n - 1):
+        currentEdge = edges[i]
+        srcp = findParent(currentEdge.src, parent)
+        destp = findParent(currentEdge.dest, parent)
+        if srcp != destp:
+            output[count] = currentEdge
+            count += 1
+            parent[srcp] = destp
+        i += 1
+
+    print("MST is:")
+    for i in range(n - 1):
+        print(output[i].src, "+", output[i].dest, "+", output[i].weight)
+
+
+n = int(input("Enter number of vertices"))
+e = int(input("Enter number of edges"))
+
+edge = Edge()
+edges = [edge] * e
+
+for i in range(e):
+    src, dest, weight = map(int, input().split())
+    edge1 = Edge()
+    edge1.src = src
+    edge1.dest = dest
+    edge1.weight = weight
+    edges[i] = edge1
+
+kruskals(edges, n, e)

Prims Algorithm

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+
+def findMinVertex(weights,n,visited):
+    minVertex=-1
+    for i in range(n):
+        if not visited[i] and (minVertex==-1 or weights[i]<weights[minVertex]):
+            minVertex=i
+    return minVertex
+
+def prims(edges,n,e):
+    visited=[False]*n
+    weights=[float("inf")]*n
+    parent=[-1]*n
+
+    weights[0]=0
+    parent[0]=-1
+
+    for i in range(n):
+        x=findMinVertex(weights,n,visited)
+        visited[x]=True
+        for j in range(n):
+            if not visited[j] and edges[x][j]!=0:
+                if edges[x][j]<weights[j]:
+                    weights[j]=edges[x][j]
+                    parent[j]=x
+    for i in range(n):
+        print(i, " ",parent[i])
+
+if __name__=="__main__":
+    n=int(input("Enter number of vertices"))
+    e=int(input("Enter number of edges"))
+
+    edges=[]*n
+    for i in range(n):
+        x=[0]*n
+        edges.append(x)
+    print(edges)
+
+    for i in range(e):
+        s,d,w=map(int,input().split())
+        edges[s][d]=w
+        edges[d][s] = w
+
+    prims(edges,n,e)