# Recursive function to pairwise swap elements of a linked list
def pairWiseSwap(head):
# There must be at-least two nodes in the list
if (head != None and head.next != None):
# Swap the node's data with data of next node
swap(head.data, head.next.data);
# Call pairWiseSwap() for rest of the list
pairWiseSwap(head.next.next);
# This code is contributed by _saurabh_jaiswal# Python program to swap the elements of linked list pairwise
# Node class
class Node:
# Constructor to initialize the node object
def __init__(self, data):
self.data = data
self.next = None
class LinkedList:
# Function to initialize head
def __init__(self):
self.head = None
# Function to pairwise swap elements of a linked list
def pairwiseSwap(self):
temp = self.head
# There are no nodes in linked list
if temp is None:
return
# Traverse furthethr only if there are at least two
# left
while(temp and temp.next):
# If both nodes are same,
# no need to swap data
if(temp.data != temp.next.data):
# Swap data of node with its next node's data
temp.data, temp.next.data = temp.next.data, temp.data
# Move temp by 2 to the next pair
temp = temp.next.next
# Function to insert a new node at the beginning
def push(self, new_data):
new_node = Node(new_data)
new_node.next = self.head
self.head = new_node
# Utility function to print the linked LinkedList
def printList(self):
temp = self.head
while(temp):
print temp.data,
temp = temp.next
# Driver program
llist = LinkedList()
llist.push(5)
llist.push(4)
llist.push(3)
llist.push(2)
llist.push(1)
print "Linked list before calling pairWiseSwap() "
llist.printList()
llist.pairwiseSwap()
print "
Linked list after calling pairWiseSwap()"
llist.printList()
# This code is contributed by Nikhil Kumar Singh(nickzuck_007)