Python/graphs/minimum_spanning_tree_kruskal.py
Christian Clauss 47a9ea2b0b
Simplify code by dropping support for legacy Python (#1143)
* Simplify code by dropping support for legacy Python

* sort() --> sorted()
2019-08-19 15:37:49 +02:00

33 lines
859 B
Python

if __name__ == "__main__":
num_nodes, num_edges = list(map(int, input().strip().split()))
edges = []
for i in range(num_edges):
node1, node2, cost = list(map(int, input().strip().split()))
edges.append((i,node1,node2,cost))
edges = sorted(edges, key=lambda edge: edge[3])
parent = list(range(num_nodes))
def find_parent(i):
if i != parent[i]:
parent[i] = find_parent(parent[i])
return parent[i]
minimum_spanning_tree_cost = 0
minimum_spanning_tree = []
for edge in edges:
parent_a = find_parent(edge[1])
parent_b = find_parent(edge[2])
if parent_a != parent_b:
minimum_spanning_tree_cost += edge[3]
minimum_spanning_tree.append(edge)
parent[parent_a] = parent_b
print(minimum_spanning_tree_cost)
for edge in minimum_spanning_tree:
print(edge)