DFS_BFS.txt

from collections import deque

# Recursive DFS function
def dfs(node, visited, graph):
    if node not in visited:
        print(node, end=' ')
        visited.add(node)
        for neighbor in graph[node]:
            dfs(neighbor, visited, graph)

# Recursive BFS function (using a helper function to simulate queue)
def bfs(queue, visited, graph):
    if not queue:
        return
    node = queue.popleft()
    if node not in visited:
        print(node, end=' ')
        visited.add(node)
        for neighbor in graph[node]:
            if neighbor not in visited:
                queue.append(neighbor)
    bfs(queue, visited, graph)

# -------- Input Graph --------
graph = {}
num_edges = int(input("Enter number of edges: "))
for _ in range(num_edges):
    u, v = map(int, input("Enter edge (u v): ").split())
    graph.setdefault(u, []).append(v)
    graph.setdefault(v, []).append(u)  # undirected

start = int(input("Enter starting node: "))

# -------- Traversals --------
# BFS Traversal (recursive)
print("BFS Traversal:", end=' ')
visited_bfs = set()
queue_bfs = deque([start])
bfs(queue_bfs, visited_bfs, graph)

# DFS Traversal (recursive)
print("\nDFS Traversal:", end=' ')
visited_dfs = set()
dfs(start, visited_dfs, graph)