binary-tree.py

from queue import Queue


class BinaryTree:
    def __init__(self, value):
        self.value = value
        self.left_child = None
        self.right_child = None

    def insert_left(self, value):
        if self.left_child is None:
            self.left_child = BinaryTree(value)
        else:
            new_node = BinaryTree(value)
            new_node.left_child = self.left_child
            self.left_child = new_node

    def insert_right(self, value):
        if self.right_child is None:
            self.right_child = BinaryTree(value)
        else:
            new_node = BinaryTree(value)
            new_node.right_child = self.right_child
            self.right_child = new_node

    # DFS

    # Data traversal
    def pre_order(self):
        print(self.value)
        if self.left_child:
            self.left_child.pre_order()
        if self.right_child:
            self.right_child.pre_order()

    def in_order(self):
        if self.left_child:
            self.left_child.in_order()
        print(self.value)
        if self.right_child:
            self.right_child.in_order()

    def post_order(self):
        if self.left_child:
            self.left_child.post_order()
        if self.right_child:
            self.right_child.post_order()
        print(self.value)

    # BFS
    def bfs(self):
        queue = Queue()
        queue.enqueue(self)
        while not queue.isEmpty():
            current_node = queue.dequeue()
            print(current_node.value)
            if current_node.left_child:
                queue.enqueue(current_node.left_child)
            if current_node.right_child:
                queue.enqueue(current_node.right_child)


if __name__ == "__main__":
    a_node = BinaryTree('a')
    a_node.insert_left('b')
    a_node.insert_right('c')

    b_node = a_node.left_child
    b_node.insert_right('d')

    c_node = a_node.right_child
    c_node.insert_left('e')
    c_node.insert_right('f')

    d_node = b_node.right_child
    e_node = c_node.left_child
    f_node = c_node.right_child

    # DFS
    # print(a_node.pre_order())
    # print(a_node.in_order())
    # print(a_node.post_order())

    # BFS
    print(a_node.bfs())  # a