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56 lines
1.1 KiB
Python
56 lines
1.1 KiB
Python
import logging
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import math
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logging.basicConfig(level=logging.DEBUG)
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logger = logging.getLogger(__name__)
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graph = {
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"start": {"a": 2, "b": 2},
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"a": {"b": 2},
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"b": {"c": 2, "fin": 2},
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"c": {"fin": 2},
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"fin": {},
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}
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costs = {
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"a": 2,
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"b": 2,
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"c": math.inf,
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"fin": math.inf,
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}
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parents = {
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"a": "start",
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"b": "start",
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"c": None,
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"fin": None,
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}
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processed = set()
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def find_lowest_cost_node(costs):
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lowest_cost = math.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.add(node)
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node = find_lowest_cost_node(costs)
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print(f"lowest cost route: {costs['fin']}")
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