Depth-first searcher in python

tree_search.py

# Write code that can search for a node in a tree.
# Return the node if it exists, and null/nil/none/undefined/false as appropriate
# in your language if not. For example, if the code is given "g" and a tree with
# the structure above, it should return the node named "g".


class Node:
  def __init__(self, name, children = []):
    self.name = name
    self.children = children

  def dfs_recursive(self, target):
    if self.name == target:
      return self

    for child in self.children:
      query = child.dfs_recursive(target)
      if query != None:
        return query

    return None


def dfs_stack(root, target):
  stack = [root]

  while len(stack) > 0:
    current = stack.pop()
    if current.name == target:
      return current
    else:
      stack.extend(current.children)

  return None


# Create a tree:
#     a
#    / \
#   b   c
#  /|\   \
# d e f   g
#         |
#         h

d = Node('d')
e = Node('e')
f = Node('f')
h = Node('h')
b = Node('b', [d,e,f])
g = Node('g', [h])
c = Node('c', [g])
a = Node('a', [b,c])