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from graph import distance, find_shortest_route
def nearest_neighbor(graph: list) -> list:
routes = []
for start_index in range(len(graph)):
routes.append(NN(graph, start_index))
return find_shortest_route(routes)
def NN(graph: list, start_index):
route = []
seen = set()
start = graph[start_index]
route.append(start)
seen.add(start)
for i in range(len(graph) - 1):
shortest_distance = None
next_town = None
for town in graph:
if town in seen:
continue
d = distance(route[-1], town)
if shortest_distance is None or d < shortest_distance:
shortest_distance = d
next_town = town
route.append(next_town)
seen.add(next_town)
route.append(start)
return route
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