生成python代码,要求:定义一个简单路网,定义一个起点和一个终点,运用dijkstra算法得到最短路径,然后将这条路径上的所有路段距离增大2倍,更新路网,继续运用dijkstra算法寻找最短路径,直至寻找到10条路径,将这10条路径里重复的路径删除,生成并输出路径集
时间: 2024-05-13 13:19:59 浏览: 79
以下是符合要求的Python代码:
```python
import heapq
# 定义简单路网
graph = {'A': {'B': 5, 'C': 1},
'B': {'A': 5, 'C': 2, 'D': 1},
'C': {'A': 1, 'B': 2, 'D': 4},
'D': {'B': 1, 'C': 4, 'E': 1},
'E': {'D': 1}}
# 定义起点和终点
start, end = 'A', 'E'
# 运用dijkstra算法得到最短路径
def dijkstra(graph, start, end):
# 初始化距离字典和前驱节点字典
dist = {node: float('inf') for node in graph}
dist[start] = 0
prev = {node: None for node in graph}
# 使用堆实现优先队列
pq = [(0, start)]
while pq:
# 取出距离最小的节点
(min_dist, curr) = heapq.heappop(pq)
# 如果当前节点已经处理过,跳过
if min_dist > dist[curr]:
continue
# 遍历当前节点的邻居节点
for neighbor, weight in graph[curr].items():
# 计算到邻居节点的距离
distance = dist[curr] + weight
# 如果计算出来的距离更小,更新距离和前驱节点
if distance < dist[neighbor]:
dist[neighbor] = distance
prev[neighbor] = curr
heapq.heappush(pq, (distance, neighbor))
# 返回最短路径
path = []
curr = end
while curr:
path.append(curr)
curr = prev[curr]
path.reverse()
return path
# 将最短路径上的所有路段距离增大2倍,更新路网
def update_graph(graph, path):
for i in range(len(path)-1):
node1, node2 = path[i], path[i+1]
graph[node1][node2] *= 2
graph[node2][node1] *= 2
# 寻找10条最短路径
paths = []
for i in range(10):
path = dijkstra(graph, start, end)
paths.append(path)
# 将最短路径上的所有路段距离增大2倍,更新路网
update_graph(graph, path)
# 删除重复路径
unique_paths = []
for path in paths:
if path not in unique_paths:
unique_paths.append(path)
# 输出路径集
for i, path in enumerate(unique_paths):
print(f"Path {i+1}: {'->'.join(path)}")
```
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