Depth-first search (DFS) code in python

Question

Can you please let me know what is incorrect in below DFS code. It\'s giving correct result AFAIK, but I don\'t know when it will fail.

graph1 = {
    \'A\'          


        

Answer 1

Without recursion:

def dfs(graph, node):
    visited = [node]
    stack = [node]
    while stack:
        node = stack[-1]
        if node not in visited:
            visited.extend(node)
        remove_from_stack = True
        for next in graph[node]:
            if next not in visited:
                stack.extend(next)
                remove_from_stack = False
                break
        if remove_from_stack:
            stack.pop()
    return visited

print (dfs(graph1, 'A'))

Output:

['A', 'B', 'S', 'C', 'D', 'E', 'H', 'G', 'F']