Python Program For Moving All Occurrences Of An Element To End In A Linked List

# Python3 program to move all occurrences of a
# given key to end.

# Linked List node 
class Node: 
    def __init__(self, data): 
        self.data = data 
        self.next = None

# A utility function to create a new node.
def newNode(x):

    temp = Node(0)
    temp.data = x
    temp.next = None
    return temp

# Utility function to print the elements
# in Linked list
def printList( head):

    temp = head
    while (temp != None) :
        print( temp.data,end = " ")
        temp = temp.next
    
    print()

# Moves all occurrences of given key to
# end of linked list.
def moveToEnd(head, key):

    # Keeps track of locations where key
    # is present.
    pKey = head

    # Traverse list
    pCrawl = head
    while (pCrawl != None) :
        
        # If current pointer is not same as pointer
        # to a key location, then we must have found
        # a key in linked list. We swap data of pCrawl
        # and pKey and move pKey to next position.
        if (pCrawl != pKey and pCrawl.data != key) :
            pKey.data = pCrawl.data
            pCrawl.data = key
            pKey = pKey.next
        
        # Find next position where key is present
        if (pKey.data != key):
            pKey = pKey.next

        # Moving to next Node
        pCrawl = pCrawl.next
    
    return head

# Driver code
head = newNode(10)
head.next = newNode(20)
head.next.next = newNode(10)
head.next.next.next = newNode(30)
head.next.next.next.next = newNode(40)
head.next.next.next.next.next = newNode(10)
head.next.next.next.next.next.next = newNode(60)

print("Before moveToEnd(), the Linked list is
")
printList(head)

key = 10
head = moveToEnd(head, key)

print("
After moveToEnd(), the Linked list is
")
printList(head)

# This code is contributed by Arnab Kundu

# Python3 code to remove key element to
# end of linked list
 
# A Linked list Node
class Node:
    
    def __init__(self, data):
        
        self.data = data
        self.next = None
        
# A utility function to create a new node.
def newNode(x):
    
    temp = Node(x)
    return temp

# Function to remove key to end
def keyToEnd(head, key):

    # Node to keep pointing to tail
    tail = head
    
    if (head == None):
        return None
    
    while (tail.next != None): 
        tail = tail.next
    
    # Node to point to last of linked list
    last = tail
    current = head
    prev = None
     
    # Node prev2 to point to previous
    # when head.data!=key
    prev2 = None
     
    # Loop to perform operations to 
    # remove key to end
    while (current != tail):
        if (current.data == key and prev2 == None):
            prev = current
            current = current.next
            head = current
            last.next = prev
            last = last.next
            last.next = None
            prev = None

        else:
            if (current.data == key and prev2 != None):
                prev = current
                current = current.next
                prev2.next = current
                last.next = prev
                last = last.next
                last.next = None
            
            elif (current != tail):
                prev2 = current
                current = current.next
                
    return head

# Function to display linked list
def printList(head):

    temp = head
    
    while (temp != None):
        print(temp.data, end = ' ')
        temp = temp.next
    
    print()
    
# Driver Code
if __name__=='__main__':
    
    root = newNode(5)
    root.next = newNode(2)
    root.next.next = newNode(2)
    root.next.next.next = newNode(7)
    root.next.next.next.next = newNode(2)
    root.next.next.next.next.next = newNode(2)
    root.next.next.next.next.next.next = newNode(2)
 
    key = 2
    print("Linked List before operations :")
    printList(root)
    print("Linked List after operations :")
    root = keyToEnd(root, key)
    
    printList(root)
    
# This code is contributed by rutvik_56