Here is a Python implementation of Depth-First Search (DFS) for a given undirected graph:

```python
from collections import defaultdict

class Graph:

def __init__(self, vertices):
self.V = vertices
self.graph = defaultdict(list)

def addEdge(self, u, v):
self.graph[u].append(v)

def DFSUtil(self, v, visited):
visited[v] = True
print(v, end=' ')

for i in self.graph[v]:
if visited[i] == False:
self.DFSUtil(i, visited)

def DFS(self, v):
visited = [False] * (max(self.graph) + 1)
self.DFSUtil(v, visited)

# Driver code
if __name__ == '__main__':
g = Graph(4)
g.addEdge(0, 1)
g.addEdge(0, 2)
g.addEdge(1, 2)
g.addEdge(2, 0)
g.addEdge(2, 3)
g.addEdge(3, 3)

print("DFS starting from vertex 0:")
g.DFS(0)
```

In this code, we first create a graph using the `Graph` class. The `addEdge` method is used to add an edge between two vertices in the graph. The `DFS` method is used to perform a depth-first search starting from a given vertex. The `DFSUtil` method is a utility function that is used by the `DFS` method to perform the actual depth-first search.

When you run this code, it will print the vertices in the order they are visited using DFS starting from vertex 0.

Question

Here is a Python implementation of Depth-First Search (DFS) for a given undirected graph:

```python
from collections import defaultdict

class Graph:

def __init__(self, vertices):
        self.V = vertices
        self.graph = defaultdict(list)

def addEdge(self, u, v):
        self.graph[u].append(v)

def DFSUtil(self, v, visited):
        visited[v] = True
        print(v, end=' ')

for i in self.graph[v]:
            if visited[i] == False:
                self.DFSUtil(i, visited)

def DFS(self, v):
        visited = [False] * (max(self.graph) + 1)
        self.DFSUtil(v, visited)

# Driver code
if __name__ == '__main__':
    g = Graph(4)
    g.addEdge(0, 1)
    g.addEdge(0, 2)
    g.addEdge(1, 2)
    g.addEdge(2, 0)
    g.addEdge(2, 3)
    g.addEdge(3, 3)

print("DFS starting from vertex 0:")
    g.DFS(0)
```

In this code, we first create a graph using the `Graph` class. The `addEdge` method is used to add an edge between two vertices in the graph. The `DFS` method is used to perform a depth-first search starting from a given vertex. The `DFSUtil` method is a utility function that is used by the `DFS` method to perform the actual depth-first search.

When you run this code, it will print the vertices in the order they are visited using DFS starting from vertex 0.

Knowee AI · Accepted Answer