def dfs_pre_order(tree: Tree):
visit_list = list()
stack = Stack()
# start with root node, visit it and add it to the stack
node = tree.get_root()
state = State(node)
stack.push(state)
visit_list.append(node.get_value())
while node:
if node.has_left_child() and not state.is_visited_left():
state.set_visited_left()
node = node.get_left_child()
state = State(node)
stack.push(state)
visit_list.append(node.get_value())
elif node.has_right_child() and not state.is_visited_right():
state.set_visited_right()
node = node.get_right_child()
state = State(node)
stack.push(state)
visit_list.append(node.get_value())
else:
stack.pop()
if not stack.is_empty():
state = stack.peek()
node = state.get_node()
else:
node = None
return visit_list
def breadth_first_search(tree: Tree):
queue = Queue()
visit_order = list()
queue.enqueue(tree.get_root())
while not queue.is_empty():
node = queue.dequeue()
visit_order.append(node.get_value())
if node.has_left_child():
queue.enqueue(node.get_left_child())
if node.has_right_child():
queue.enqueue(node.get_right_child())
return visit_order
def dfs_pre_order_recursion(tree: Tree):
visit_list = list()
node = tree.get_root()
# traverse
def traverse(node):
if node:
# visit the node
visit_list.append(node.get_value())
# traverse left
traverse(node.get_left_child())
# traverse right
traverse(node.get_right_child())
traverse(node)
return visit_list
from data_structures.trees.tree import Tree
from data_structures.trees.tree_node import Node
from data_structures.trees.state import State
from data_structures.stack.stack_linkedlist import Stack
# init tree
tree = Tree("apple")
tree.get_root().set_left_child(Node("banana"))
tree.get_root().set_right_child(Node("cherry"))
tree.get_root().get_left_child().set_left_child(Node("dates"))
def dfs_pre_order(tree: Tree):
visit_list = list()
stack = Stack()
# start with root node, visit it and add it to the stack
node = tree.get_root()
state = State(node)
stack.push(state)
visit_list.append(node.get_value())
while node:
if node.has_left_child() and not state.is_visited_left():
state.set_visited_left()
node = node.get_left_child()
state = State(node)
stack.push(state)
visit_list.append(node.get_value())
elif node.has_right_child() and not state.is_visited_right():
from data_structures.trees.tree import Tree
from data_structures.trees.tree_node import Node
# init tree
tree = Tree(1)
tree.insert_with_loop(2)
tree.insert_with_loop(3)
tree.insert_with_loop(5)
tree.insert_with_loop(4)
tree.insert_with_loop(0)
print(tree)
print("\n=====================")
tree = Tree(1)
tree.insert_with_recursion(2)
tree.insert_with_recursion(3)
tree.insert_with_recursion(5)
tree.insert_with_recursion(4)
tree.insert_with_recursion(0)
print(tree)
print("\n=====================")
print(tree.search(0))
print(tree.search(10))
print("\n=delete a node ====================")
tree = Tree(5)
tree.insert_with_recursion(3)
tree.insert_with_recursion(4)
tree.insert_with_recursion(7)
tree.insert_with_recursion(6)