1) Search an element in LinkedList (iterative approach)
There are various steps included in the iterative approach for search an element in a linked list and they are as follows:
Step:1 Initialize node pointer current=head
Step:2 As current-> key is not equal to given key,current=current->next(2nd node).
Step:3 As current->key is not equal to given key,current=current->next(3rd node).
Step:4 As current->key is equal to a given key,return True.
# Node class
class Node:
# Function to initialize the node object
def __init__(self, data=None, next=None):
self.data = data # Assign data
self.next = next # Initialize next as null
# Linked List class
class LinkedList:
# Function to initialize the LinkedList object
def __init__(self):
self.head = None
# print function prints contents of linked list starting from head
def print(self):
# if linked list is empty
if self.head is None:
print("Linked list is empty")
return
itr = self.head
#taking empty string and appending values
llstr = ''
while itr:
llstr += str(itr.data)+' --> '
itr = itr.next
print(llstr)
# Function to insert a new node at the beginning
def insert_at_begining(self, data):
node = Node(data, self.head)
self.head = node
# This Function checks whether the value x present in the linked list
def search_element(self,x):
# Initialize itr to head
itr = self.head
count=0
# loop till itr not equal to None
while itr!=None:
if itr.data == x:
return count # data found
itr = itr.next
count=count+1
return False # Data Not found
# Code execution starts here
if __name__ == '__main__':
ll = LinkedList()
ll.insert_at_begining(10)
ll.insert_at_begining(20)
ll.insert_at_begining(30)
ll.insert_at_begining(40)
print ("Created Linked List: ")
ll.print()
result=ll.search_element(20)
if (result>=0):
print("element found in Linkedlist at %d index",result)
else:
print("element not found")
2) Search an element in LinkedList (Recursive approach)
Various steps included in this approach are as follows:
Step:1 Head is not Null,head->key is not equal to given key.Therefore,search(head->next,key)is returned.
Step:2 Again Head is not Null,head->key is not equal to given key.Therefore,search(head->next,key)is returned.
Step:3 Again Head is not Null and head->key is equal to given key.Therefore,True is returned.
# Node class
class Node:
# Function to initialize the node object
def __init__(self, data=None, next=None):
self.data = data # Assign data
self.next = next # Initialize next as null
# Linked List class
class LinkedList:
# Function to initialize the LinkedList object
def __init__(self):
self.head = None
# print function prints contents of linked list starting from head
def print(self):
# if linked list is empty
if self.head is None:
print("Linked list is empty")
return
itr = self.head
#taking empty string and appending values
llstr = ''
while itr:
llstr += str(itr.data)+' --> '
itr = itr.next
print(llstr)
# Function to insert a new node at the beginning
def insert_at_begining(self, data):
node = Node(data, self.head)
self.head = node
# This Function checks whether the value x present in the linked list
def search_element(self,itr,x):
# if linked list is empty
if itr is None:
print("Linked list is empty")
return False
# If key is present in current node, return true
if(itr.data == x):
return True
# Recur for remaining list
return self.search_element(itr.next,x)
# Code execution starts here
if __name__ == '__main__':
ll = LinkedList()
ll.insert_at_begining(10)
ll.insert_at_begining(20)
ll.insert_at_begining(30)
ll.insert_at_begining(40)
print ("Created Linked List: ")
ll.print()
result=ll.search_element(ll.head,20)
if (result):
print("element found in Linkedlist")
else:
print("element not found")
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