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* Pyupgrade to Python 3.9
* updating DIRECTORY.md
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47 lines
1.3 KiB
Python
47 lines
1.3 KiB
Python
def kruskal(
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num_nodes: int, edges: list[tuple[int, int, int]]
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) -> list[tuple[int, int, int]]:
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"""
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>>> kruskal(4, [(0, 1, 3), (1, 2, 5), (2, 3, 1)])
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[(2, 3, 1), (0, 1, 3), (1, 2, 5)]
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>>> kruskal(4, [(0, 1, 3), (1, 2, 5), (2, 3, 1), (0, 2, 1), (0, 3, 2)])
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[(2, 3, 1), (0, 2, 1), (0, 1, 3)]
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>>> kruskal(4, [(0, 1, 3), (1, 2, 5), (2, 3, 1), (0, 2, 1), (0, 3, 2),
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... (2, 1, 1)])
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[(2, 3, 1), (0, 2, 1), (2, 1, 1)]
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"""
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edges = sorted(edges, key=lambda edge: edge[2])
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parent = list(range(num_nodes))
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def find_parent(i):
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if i != parent[i]:
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parent[i] = find_parent(parent[i])
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return parent[i]
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minimum_spanning_tree_cost = 0
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minimum_spanning_tree = []
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for edge in edges:
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parent_a = find_parent(edge[0])
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parent_b = find_parent(edge[1])
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if parent_a != parent_b:
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minimum_spanning_tree_cost += edge[2]
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minimum_spanning_tree.append(edge)
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parent[parent_a] = parent_b
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return minimum_spanning_tree
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if __name__ == "__main__": # pragma: no cover
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num_nodes, num_edges = list(map(int, input().strip().split()))
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edges = []
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for _ in range(num_edges):
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node1, node2, cost = (int(x) for x in input().strip().split())
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edges.append((node1, node2, cost))
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kruskal(num_nodes, edges)
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