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105 lines
3.0 KiB
Python
105 lines
3.0 KiB
Python
class Node: # create a Node
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def __init__(self, data):
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self.data = data # given data
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self.next = None # given next to None
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class Linked_List:
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def __init__(self):
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self.head = None # Initialize head to None
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def insert_tail(self, data):
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if self.head is None:
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self.insert_head(data) # If this is first node, call insert_head
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else:
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temp = self.head
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while temp.next != None: # traverse to last node
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temp = temp.next
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temp.next = Node(data) # create node & link to tail
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def insert_head(self, data):
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newNod = Node(data) # create a new node
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if self.head != None:
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newNod.next = self.head # link newNode to head
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self.head = newNod # make NewNode as head
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def printList(self): # print every node data
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temp = self.head
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while temp is not None:
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print(temp.data)
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temp = temp.next
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def delete_head(self): # delete from head
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temp = self.head
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if self.head != None:
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self.head = self.head.next
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temp.next = None
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return temp
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def delete_tail(self): # delete from tail
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temp = self.head
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if self.head != None:
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if self.head.next is None: # if head is the only Node in the Linked List
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self.head = None
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else:
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while temp.next.next is not None: # find the 2nd last element
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temp = temp.next
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temp.next, temp = (
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None,
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temp.next,
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) # (2nd last element).next = None and temp = last element
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return temp
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def isEmpty(self):
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return self.head is None # Return if head is none
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def reverse(self):
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prev = None
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current = self.head
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while current:
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# Store the current node's next node.
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next_node = current.next
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# Make the current node's next point backwards
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current.next = prev
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# Make the previous node be the current node
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prev = current
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# Make the current node the next node (to progress iteration)
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current = next_node
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# Return prev in order to put the head at the end
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self.head = prev
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def main():
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A = Linked_List()
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print("Inserting 1st at head")
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a1 = input()
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A.insert_head(a1)
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print("Inserting 2nd at head")
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a2 = input()
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A.insert_head(a2)
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print("\nPrint List : ")
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A.printList()
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print("\nInserting 1st at Tail")
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a3 = input()
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A.insert_tail(a3)
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print("Inserting 2nd at Tail")
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a4 = input()
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A.insert_tail(a4)
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print("\nPrint List : ")
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A.printList()
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print("\nDelete head")
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A.delete_head()
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print("Delete Tail")
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A.delete_tail()
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print("\nPrint List : ")
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A.printList()
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print("\nReverse Linked List")
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A.reverse()
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print("\nPrint List : ")
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A.printList()
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if __name__ == "__main__":
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main()
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