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- class Graph:
- def __init__(self):
- self.nodes = set()
- self.edges = defaultdict(list)
- self.distances = {}
- def add_node(self, value):
- self.nodes.add(value)
- def add_edge(self, from_node, to_node, distance):
- self.edges[from_node].append(to_node)
- self.edges[to_node].append(from_node)
- self.distances[(from_node, to_node)] = distance
- def dijsktra(graph, initial):
- visited = {initial: 0}
- path = {}
- nodes = set(graph.nodes)
- while nodes:
- min_node = None
- for node in nodes:
- if node in visited:
- if min_node is None:
- min_node = node
- elif visited[node] < visited[min_node]:
- min_node = node
- if min_node is None:
- break
- nodes.remove(min_node)
- current_weight = visited[min_node]
- for edge in graph.edges[min_node]:
- weight = current_weight + graph.distance[(min_node, edge)]
- if edge not in visited or weight < visited[edge]:
- visited[edge] = weight
- path[edge] = min_node
- return visited, path
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