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Commit c86829c

Browse files
Update1: Linkedlist and Stack
0 parents commit c86829c

8 files changed

+786
-0
lines changed

‎Linked_list_functions.py

Lines changed: 189 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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class Node:
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def __init__(self, data=None, next=None):
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self.data=data
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self.next=next
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class LinkedList:
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def __init__(self):
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self.head=None
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def check_empty(self):
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if self.head is None:
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return True
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return False
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def insert(self, data):
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if self.head is None:
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self.head=Node(data, None)
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return
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itr=self.head
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while itr.next:
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itr=itr.next
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itr.next=Node(data, None)
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def search_by_data(self, data):
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'''here, if data is found then we'll return it's index position'''
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if not self.head:
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print("LL is empty, can't perform search")
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return
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position=0
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itr=self.head
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while itr:
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if itr.data==data:
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print(f"data present at index:{position}")
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break
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position+=1
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itr=itr.next
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else:
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print("data not present")
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def find_ref_to_node(self, data):
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'''here we'll find the next reference of given data'''
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if self.head is None:
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print("LL is empty")
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return
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itr=self.head
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while itr:
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if itr.data==data:
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if itr.next is None:
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print("Current node is pointing to None")
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break
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print("Current node is pointing to:", str(itr.next.data))
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return
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itr=itr.next
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def insert_after_given_node(self,node_data,insert_data ):
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try:
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assert self.head is not None
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except AssertionError:
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print("LL is empty")
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else:
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itr=self.head
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while itr:
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if itr.data == node_data:
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node=Node(insert_data, itr.next)
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itr.next=node
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break
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itr=itr.next
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def delete_at_beginning(self):
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if self.head is None:
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print("LL is empty")
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return
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self.head=self.head.next
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def deletion_last_node(self):
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if self.head is None:
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print("LL is empty")
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return
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itr=self.head
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while itr:
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if itr.next.next is None:
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itr.next=None
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itr=itr.next
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def delete_node(self, data):
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if self.head is None:
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print("LL is empty")
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return
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itr=self.head
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if self.head.data==data:
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self.head=self.head.next
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return
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while itr:
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if itr.next is None:
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print("value not available in the LinkedList")
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break
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if itr.next.data==data:
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itr.next=itr.next.next
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break
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itr=itr.next
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else:
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print("data not founds")
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def find_miidle(self):
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if self.head is None:
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print("LL is empty")
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return
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slow_ptr=self.head
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fast_ptr=self.head
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while fast_ptr and fast_ptr.next:
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# if fast_ptr.next.next is None:
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# print("middle of LL is", str(slow_ptr.data))
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# break
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slow_ptr=slow_ptr.next
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fast_ptr=fast_ptr.next.next
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print("middle of LL is", str(slow_ptr.data))
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def get_len(self):
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if self.head is None:
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return 0
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itr=self.head
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count=0
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while itr:
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count+=1
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itr=itr.next
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return count
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def reverse_LL(self):
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current=self.head
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prev=None
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while current !=None:
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temp=current.next
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current.next=prev
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prev=current
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current=temp
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self.head=prev
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def display_LL(self):
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if self.head is None:
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print("LL is empty")
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return
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itr=self.head
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while itr:
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print(itr.data,end="-->")
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# print("%d"%(itr.data),end="-->")
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itr=itr.next
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print()
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'''
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LL=LinkedList()
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LL.insert(10)
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LL.insert(20)
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LL.insert(30)
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LL.insert(40)
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LL.insert(50)
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LL.insert(60)
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LL.display_LL()
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LL.search_by_data(30)
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LL.find_ref_to_node(20)
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# print(LL.find_ref_to_node.__doc__)
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LL.insert_after_given_node(10, 15)
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LL.display_LL()
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LL.delete_at_beginning()
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LL.display_LL()
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LL.deletion_last_node()
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LL.display_LL()
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LL.delete_node(20)
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LL.display_LL()
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LL.find_miidle()
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print(LL.get_len())'''
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LL=LinkedList()
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LL.insert(10)
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LL.insert(20)
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LL.insert(30)
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LL.insert(40)
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LL.reverse_LL()
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LL.display_LL()
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# LL.insert(10)
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# LL.insert(20)
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# LL.insert(30)
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# LL.insert(40)
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# LL.find_miidle()

‎doubly_linked_list.py

Lines changed: 166 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,166 @@
1+
# for garbege collection
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import gc
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class Node:
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def __init__(self, data= None, prev= None, next= None,):
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self.data=data
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self.next=next
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self.prev=prev
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class Doubly_linked_list:
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def __init__(self):
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self.head=None
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def insert_at_beginning(self, data):
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# check if DLL is empty
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if self.head is None:
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# if empty insert at beginning
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node=Node(data, None, None)
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# now head will point to newly created node
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self.head=node
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return
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# if not empty create a node pointing to current head
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node=Node(data,None, self.head )
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# now hwad will be marked as newly created node bcz we're inserting at beginning
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self.head=node
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def delete_beginning(self):
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if self.head is None:
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print("DLL is Empty")
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return
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self.head=self.head.next
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self.head.prev=None
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35+
def delete_end(self):
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if self.head is None:
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print("DLL is empty")
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return
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itr=self.head
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while itr.next.next:
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itr=itr.next
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itr.next=None
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44+
def insert_at_end(self, data):
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# check if DLL is empty
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if self.head is None:
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# if empty insert at beginning
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self.insert_at_beginning(data)
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return
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# if not empty, travese till end
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# head will be assigned to iterator
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itr=self.head
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# it will iterate untill itr.next points to None i.e. it has reached end
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while itr.next:
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# each step, next node will be assigned to iterator
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itr=itr.next
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# we've reached att end, so we'll create a new node
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# whose prev will point to current last node(itr) and end will point to None
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node=Node(data, itr, None)
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itr.next=node
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def get_len(self):
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if self.head is None:
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return 0
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count=0
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itr=self.head
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while itr:
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count+=1
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itr=itr.next
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return count
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def delete_node_by_val(self, data):
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if self.head is None:
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print("DLL is empty")
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return
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# if data present at beginning
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if self.head.data==data:
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self.delete_beginning()
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return
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itr=self.head
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# if node is in between start and end
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while itr.next.next:
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if itr.next.data==data:
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temp=itr.next.next
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itr.next=itr.next.next
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temp.prev=itr
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return
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itr=itr.next
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# if node present at the end
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if itr.next.data==data:
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self.delete_end()
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else:
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print(f"node containing data {data} is not present in DLL")
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gc.collect()
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def insert_after_node(self, node_data, insert_data):
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if self.head is None:
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print("DLL is empty")
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return
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itr=self.head
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while itr.next:
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if itr.data==node_data:
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temp=itr.next
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node=Node(insert_data, itr,itr.next)
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itr.next=node
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temp.prev=node
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break
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itr=itr.next
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if itr.data==node_data:
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self.insert_at_end(insert_data)
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else:
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print(f"node data {node_data} not present in DLL")
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def print_doubly_LL(self):
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# check if empty
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if self.head is None:
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print("Doubly LL is empty")
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return
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# if not empty, iterate and print
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itr=self.head
125+
while itr:
126+
print(str(itr.data),end="-->")
127+
itr=itr.next
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print()
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def print_reverse_DLL(self):
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if self.head is None:
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print("DLL is empty")
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return
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itr=self.head
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# here we'll get the last node
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while itr.next:
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itr=itr.next
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# we have it as our last node
139+
while itr:
140+
print(str(itr.data),end="-->")
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itr=itr.prev
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'''DLL=Doubly_linked_list()
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DLL.insert_at_beginning(10)
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DLL.insert_at_beginning(20)
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DLL.insert_at_beginning(30)
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DLL.insert_at_beginning(40)
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DLL.print_doubly_LL()'''
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DLL=Doubly_linked_list()
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DLL.insert_at_end(10)
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DLL.insert_at_end(20)
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DLL.insert_at_end(30)
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DLL.insert_at_end(40)
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DLL.insert_at_end(50)
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DLL.print_doubly_LL()
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DLL.insert_after_node(50, 60)
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DLL.print_doubly_LL()
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# DLL.delete_node_by_val(10)
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# DLL.print_doubly_LL()
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# DLL.print_doubly_LL()
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# DLL.delete_beginning()
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# DLL.delete_end()
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# DLL.print_doubly_LL()
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# print(DLL.get_len())
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DLL.print_reverse_DLL()

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