AlgoDatSoSe25/vorlesung/L05_binaere_baeume/bin_tree.py

from vorlesung.L05_binaere_baeume.bin_tree_node import BinaryTreeNode
from utils.project_dir import get_path
from datetime import datetime


class BinaryTree:

    def __init__(self):
        self.root = None
        self.size = 0

    def new_node(self, value):
        return BinaryTreeNode(value)

    def insert(self, value):
        self.size += 1
        if self.root is None:
            self.root = self.new_node(value)
            return self.root, None
        else:
            current = self.root
            while True:
                if value < current.value:
                    if current.left:
                        current = current.left
                    else:
                        current.left = self.new_node(value)
                        return current.left, current
                elif value >= current.value:
                    if current.right:
                        current = current.right
                    else:
                        current.right = self.new_node(value)
                        return current.right, current
                else:
                    return None, None

    def search(self, value):
        current = self.root
        while current:
            if value < current.value:
                current = current.left
            elif value > current.value:
                current = current.right
            else:
                return current
        return None

    def delete(self, value):
        # Der Wert wird im Baum gesucht und der erste Treffer gelöscht
        # Rückgabe falls der Wert gefunden wird:
        # der Knoten, der den zu löschenden Knoten ersetzt und der Elternknoten des gelöschten Knotens
        parent = None
        current = self.root
        while current:
            if value < current.value:
                parent = current
                current = current.left
            elif value > current.value:
                parent = current
                current = current.right
            else:
                # Knoten gefunden
                break
        else:
            # Wert nicht gefunden
            return
        return self.delete_node(current, parent)

    def delete_node(self, current, parent):
        # Der übergebene Knoten wird
        # Rückgabe ist ein Tupel:
        # der Knoten, der den zu löschenden Knoten ersetzt und der Elternknoten des gelöschten Knotens
        self.size -= 1
        # Fall 3: Es gibt zwei Kinder: wir suchen den Nachfolger
        if current.left and current.right:
            parent = current
            successor = current.right
            while successor.left:
                parent = successor
                successor = successor.left
            # Wert des Nachfolgers wird in den Knoten geschrieben, der gelöscht werden soll
            current.value = successor.value
            # Ab jetzt muss successor gelöscht werden; parent ist bereits richtig gesetzt
            current = successor

        # Ermitteln des einen Kindes (falls es eines gibt), sonst None
        # Das eine Kind ist der Ersatz für den Knoten, der gelöscht werden soll
        if current.left:
            child = current.left
        else:
            child = current.right

        # Falls es keinen Elternknoten gibt, ist der Ersatzknoten die Wurzel
        if not parent:
            self.root = child
            return child, None
        elif parent.left == current:
            parent.left = child
            return child, parent
        else:
            parent.right = child
            return child, parent


    def in_order_traversal(self, callback):

        def in_order_traversal_recursive(callback, current):
            if current is not None:
                in_order_traversal_recursive(callback, current.left)
                callback(current)
                in_order_traversal_recursive(callback, current.right)

        in_order_traversal_recursive(callback, self.root)


    def level_order_traversal(self, callback):
        if self.root is None:
            return
        queue = [(self.root, 0)]
        while queue:
            current, level = queue.pop(0)
            callback(current, level)
            if current.left is not None:
                queue.append((current.left, level + 1))
            if current.right is not None:
                queue.append((current.right, level + 1))

    def tree_structure_traversal(self, callback):

        def tree_structure_traversal_recursive(callback, current, level):
            nonlocal line
            if current:
                tree_structure_traversal_recursive(callback, current.left, level + 1)
                callback(current, level, line)
                line += 1
                tree_structure_traversal_recursive(callback, current.right, level + 1)

        line = 0
        tree_structure_traversal_recursive(callback, self.root, 0)


    def graph_traversal(self):

        def define_node(node, level, line):
            nonlocal file
            if node is not None:
                file.write(node.gv_rep(level, line))

        def graph_traversal_recursive(current):
            nonlocal file
            if current is not None:
                if current.left:
                    file.write(f"{id(current)} -> {id(current.left)}; \n")
                    graph_traversal_recursive(current.left)
                if current.right:
                    file.write(f"{id(current)} -> {id(current.right)}; \n")
                    graph_traversal_recursive(current.right)

        timestamp = datetime.now().strftime("%Y%m%d_%H:%M:%S")
        filename = f"graph_{timestamp}.gv"
        filename = get_path(filename)
        with open(filename, "w") as file:
            file.write("digraph BST {\n")
            file.write("layout=neato;\n")
            file.write("node [shape=circle, fontname=\"Arial\"];\n")
            self.tree_structure_traversal(define_node)
            graph_traversal_recursive(self.root)
            file.write("}")




if __name__ == "__main__":
    tree = BinaryTree()
    values = [5, 3, 7, 2, 4, 6, 5, 8]

    for value in values:
        tree.insert(value)

    def print_node(node, indent=0, line=None):
        print((indent * 3) * " ", node.value)


    print("In-order traversal:")
    tree.in_order_traversal(print_node)
    print("\nLevel-order traversal:")
    tree.level_order_traversal(print_node)
    print("\nTree structure traversal:")
    tree.tree_structure_traversal(print_node)
    print("\nGraph traversal:")
    tree.graph_traversal()

    print("\nDeleting 5:")
    tree.delete(5)

    print("In-order traversal after deletion:")
    tree.in_order_traversal(print_node)
    print("\nLevel-order traversal after deletion:")
    tree.level_order_traversal(print_node)
    print("\nTree structure traversal after deletion:")
    tree.tree_structure_traversal(print_node)