72 lines
1.8 KiB
Python
72 lines
1.8 KiB
Python
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from abc import ABC, abstractmethod
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class ListeElement(ABC):
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@abstractmethod
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def length(self):
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pass
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class Element(ListeElement):
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def __init__(self, data):
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self.data = data
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self.next = None
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def length(self):
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# Rekursive Methode zur Berechnung der Länge
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return 1 + self.next.length()
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class Abschluss(ListeElement):
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def length(self):
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# Ein Abschluss hat keine Länge
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return 0
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class Liste:
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def __init__(self):
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self.head = Abschluss() # Der Kopf der Liste ist ein Abschluss
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def insert(self, value):
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new_element = Element(value)
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new_element.next = self.head
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self.head = new_element
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def remove_first(self):
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if isinstance(self.head, Abschluss):
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return # Liste ist leer
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self.head = self.head.next
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def length(self):
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return self.head.length()
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def show_list(self):
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current = self.head
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while not isinstance(current, Abschluss):
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print(current.data)
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current = current.next
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def search(self, value):
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current = self.head
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while not isinstance(current, Abschluss):
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if current.data == value:
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return current
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current = current.next
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return None
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def insert_before(self, value, comp_value):
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new_element = Element(value)
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if isinstance(self.head, Abschluss):
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return # Liste ist leer
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if self.head.data == comp_value:
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new_element.next = self.head
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self.head = new_element
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return
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current = self.head
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while current.next is not None and current.next.data != comp_value:
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current = current.next
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if current.next is not None:
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new_element.next = current.next
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current.next = new_element
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