62 lines
1.2 KiB
Plaintext
62 lines
1.2 KiB
Plaintext
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graph = {}
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infinity = float("inf")
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graph["start"] = {}
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graph["start"]["a"] = 6
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graph["start"]["b"] = 2
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graph["start"]["c"] = infinity
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graph["a"] = {}
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graph["a"]["c"] = 4
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graph["b"] = {}
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graph["b"]["a"] = 3
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graph["b"]["fin"] = infinity
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graph["b"]["c"] = 8
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graph["c"] = {}
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graph["c"]["fin"] = 6
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graph["fin"] = {}
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costs = {}
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costs["a"] = 6
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costs["b"] = 2
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costs["c"] = infinity
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costs["fin"] = infinity
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parents = {}
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parents["a"] = "start"
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parents["b"] = "start"
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parents["fin"] = "c"
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parents["c"] = "a"
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parents["c"] = "b"
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processed = []
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def find_lowest_cost_node(costs):
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lowest_cost = float("inf")
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lowest_cost_node = None
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for node in costs:
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cost = costs[node]
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if cost < lowest_cost and node not in processed:
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lowest_cost = cost
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lowest_cost_node = node
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return lowest_cost_node
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node = find_lowest_cost_node(costs)
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while node is not None:
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cost = costs[node]
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neighbors = graph[node]
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for n in neighbors.keys():
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new_cost = cost + neighbors[n]
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if costs[n] > new_cost:
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costs[n] = new_cost
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parents[n] = node
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processed.append(node)
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node = find_lowest_cost_node(costs)
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print("Cost from the start to each node:")
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print(costs)
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print(parents)
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