DFS algorithm in Python

DFS algorithm

def dfs(graph, start, visited=None): if visited is None: visited = set() visited.add(start)

print(start)

for next in graph[start] - visited:
    dfs(graph, next, visited)
return visited

graph = {'0': set(['1', '2']), '1': set(['0', '3', '4']), '2': set(['0']), '3': set(['1']), '4': set(['2', '3'])}

dfs(graph, '0')

BFS algorithm in Python

import collections

BFS algorithm

def bfs(graph, root):

visited, queue = set(), collections.deque([root])
visited.add(root)

while queue:

    # Dequeue a vertex from queue
    vertex = queue.popleft()
    print(str(vertex) + " ", end="")

    # If not visited, mark it as visited, and
    # enqueue it
    for neighbour in graph[vertex]:
        if neighbour not in visited:
            visited.add(neighbour)
            queue.append(neighbour)

if __name__ == '__main__': graph = {0: [1, 2], 1: [2], 2: [3], 3: [1, 2]} print("Following is Breadth First Traversal: ") bfs(graph, 0)