How do I implement Depth-First Search in Python?

How do I implement Depth-First Search in Python?

To implement Depth-First Search (DFS) in Python, you can use either recursion or a stack. Which method would you prefer?

I think I'd like to see the recursive method.

Great choice! Here's a simple recursive implementation:

def dfs_recursive(graph, node, visited=None):
    if visited is None:
        visited = set()
    visited.add(node)
    for neighbor in graph[node]:
        if neighbor not in visited:
            dfs_recursive(graph, neighbor, visited)
    return visited

Would you like an example of how to use this function?

Yes, please provide an example.

Sure! Here's how you can use the dfs_recursive function:

# Example graph represented as an adjacency list
graph = {
    'A': ['B', 'C'],
    'B': ['D', 'E'],
    'C': ['F'],
    'D': [],
    'E': ['F'],
    'F': []
}

# Starting DFS from node 'A'
visited_nodes = dfs_recursive(graph, 'A')
print(visited_nodes)  # Output: {'A', 'B', 'D', 'E', 'F', 'C'}

This will visit all nodes reachable from 'A'. Do you have any other questions?