def swap_path(tour, i, j, dist):
A = tour[i]
swaped_tour = tour.copy()
swaped_tour.remove(A)
swaped_tour.insert(j, A)
if get_tour_length(swaped_tour, dist) < get_tour_length(tour, dist):
tour.remove(A)
tour.insert(j, A)
def improve_tour(dist, tour):
N = len(tour)
can_improve = True
while can_improve:
original_length = get_tour_length(tour, dist)
for i in range(N):
for j in range(i + 2, N):
swap_path(tour, i, j, dist)
if get_tour_length(tour, dist) >= original_length:
can_improve = False
def improve_tour2(dist, tour):
N = len(tour)
can_improve = True
while can_improve:
original_length = get_tour_length(tour, dist)
for i in range(N):
# 閾値を超えている都市にだけ適用
if dist[i][(i + 1) % N] + dist[(i + 1) % N][(i + 2) % N] < 1500:
continue
for j in range(N):
swap_path(tour, i, j, dist)
if get_tour_length(tour, dist) >= original_length:
can_improve = False
def improve_tour2(dist, tour):
N = len(tour)
can_improve = True
while can_improve:
original_length = get_tour_length(tour, dist)
for i in range(N):
# 計算量削減のため近傍都市(かつ経路でiより後ろの都市)のみ探索
neighbor_city = get_neighbor_city(dist[i])
remaining_tour = set(tour[i + 1:])
neighbor_city_index = [
tour.index(city) for city in neighbor_city & remaining_tour
]
for j in neighbor_city_index:
# for j in range(i+2, N):
swap_path(tour, i, j, dist)
if get_tour_length(tour, dist) >= original_length:
can_improve = False
def solve(cities):
N = len(cities)
dist = get_all_distance(cities)
tours = []
# スタート地点を変えて実行する
for i in range(N):
tours.append(solve_each(dist, i))
tours_length = [get_tour_length(tour, dist) for tour in tours]
shortest_tour = tours[tours_length.index(min(tours_length))]
# 一番短い経路を返す
return shortest_tour
def solve(cities):
N = len(cities)
start_points = range(N)
# challenge6はランダムな点一つで実行
if N >= 2048:
start_points = [random.randint(0, N - 1)]
# 全ての距離
dist = get_all_distance(cities)
tours = []
# スタート地点を変えて実行する
for i in start_points:
tours.append(solve_each(dist, i))
tours_length = [get_tour_length(tour, dist) for tour in tours]
shortest_tour = tours[tours_length.index(min(tours_length))]
# 一番短い経路を返す
return shortest_tour
def solve(cities):
N = len(cities)
start_points = range(N)
tours = []
dist = [[0] * N for i in range(N)]
# 距離記録
for i in range(N):
for j in range(i, N):
dist[i][j] = dist[j][i] = distance(cities[i], cities[j])
# challenge6, 7: ランダムに選んだ1点で実行
if N >= 2048:
start_points = [random.randint(0, N-1)]
# スタート地点を変えて実行
for i in start_points:
tours.append(solve_each(dist, i))
tours_length = [get_tour_length(tour, dist) for tour in tours]
shortest_tour = tours[tours_length.index(min(tours_length))]
return shortest_tour
def solve(cities):
N = len(cities)
tours = []
dist = [[0] * N for i in range(N)]
# 距離記録
for i in range(N):
for j in range(i, N):
dist[i][j] = dist[j][i] = distance(cities[i], cities[j])
# challenge6: ランダムに選んだ1点で実行
#if N >= 2048:
#start_points = [random.randint(0, N-1)]
# ALEX_COMMENT: the loop below is N * the greedy.
# thats very expensive - even though it may be precise
# スタート地点を変えて実行
for i in range(N):
tours.append(solve_each(dist, i))
tours_length = [get_tour_length(tour, dist) for tour in tours]
shortest_tour = tours[tours_length.index(min(tours_length))]
return shortest_tour