BFS python
时间: 2023-11-09 09:00:07 浏览: 51
BFS(广度优先搜索)是一种用于图形遍历的算法,它从起始节点开始,逐层扩展搜索,直到找到目标节点或遍历完整个图形。下面是一个使用Python实现BFS的示例代码:
```python
from collections import deque
def bfs(graph, start):
visited = set()
queue = deque([start])
while queue:
node = queue.popleft()
print(node)
if node not in visited:
visited.add(node)
neighbors = graph[node]
queue.extend(neighbors)
# 示例图形
graph = {
'A': ['B', 'C'],
'B': ['D', 'E'],
'C': ['F'],
'D': [],
'E': ['F'],
'F': ['G'],
'G': []
}
bfs(graph, 'A')
```
这段代码通过使用`deque`队列来实现BFS。它从起始节点开始,将其加入队列中并标记为已访问。然后,它循环遍历队列,弹出队列中的节点并打印。接着,将该节点的未访问邻居加入队列中,并将当前节点标记为已访问。这个过程会持续进行,直到队列为空。
相关问题
dfs和bfs python
深度优先搜索(DFS)和广度优先搜索(BFS)是常用的图搜索算法,它们可以应用于迷宫、排列组合、树结构等问题。下面是Python实现DFS和BFS的样例代码:
DFS:
```python
def dfs(graph, start, visited=set()):
visited.add(start)
for next_node in graph[start] - visited:
dfs(graph, next_node, visited)
return visited
```
BFS:
```python
def bfs(graph, start):
visited, queue = set(), [start]
visited.add(start)
while queue:
node = queue.pop(0)
for next_node in graph[node] - visited:
visited.add(next_node)
queue.append(next_node)
return visited
```
其中,graph表示图结构,start表示起点节点。在DFS中,visited用于记录已访问的节点。在BFS中,queue用于记录待访问节点。
kevin bacon game bfs python
The Kevin Bacon game is a popular trivia game that is played by connecting Hollywood actors to Kevin Bacon through their movies. The game has inspired various computer-based versions, including one that is implemented using the breadth-first search (BFS) algorithm in Python.
Breadth-first search is a graph traversal algorithm that operates by exploring all the vertices at a given depth before moving on to the vertices at the next depth level. This makes it a perfect algorithm for traversing the relationship network of movie stars and linking them to Kevin Bacon.
To implement the Kevin Bacon game using BFS in Python, the first step is to represent the relationships between the actors and movies as a graph. This can be done using an adjacency list or adjacency matrix representation. Once the graph is created, the BFS algorithm can be applied to traverse the graph and find the shortest path between two actors.
The BFS algorithm starts with the starting actor – in this case, Kevin Bacon – and explores all the actors connected to him through the movies they have starred in. Then, it examines all the actors connected to these actors, and so on until the target actor is found. Along the way, the algorithm keeps track of the path taken to reach the target actor.
The Python implementation of the Kevin Bacon game using BFS is a fun and interactive way to explore the relationships between Hollywood actors and their movies. It is also a great example of the versatile uses of graph traversal algorithms like BFS in solving real-world problems.