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enhance swapping code in link #1660

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69 changes: 26 additions & 43 deletions data_structures/linked_list/swap_nodes.py
Original file line number Diff line number Diff line change
@@ -1,72 +1,55 @@
from typing import Any


class Node:
def __init__(self, data):
def __init__(self, data: Any):
self.data = data
self.next = None


class Linkedlist:
class LinkedList:
def __init__(self):
self.head = None

def print_list(self):
temp = self.head
while temp is not None:
print(temp.data)
print(temp.data, end=' ')
temp = temp.next
print()

# adding nodes
def push(self, new_data):
def push(self, new_data: Any):
new_node = Node(new_data)
new_node.next = self.head
self.head = new_node

# swapping nodes
def swapNodes(self, d1, d2):
prevD1 = None
prevD2 = None
if d1 == d2:
def swap_nodes(self, node_data_1, node_data_2):
if node_data_1 == node_data_2:
return
else:
# find d1
D1 = self.head
while D1 is not None and D1.data != d1:
prevD1 = D1
D1 = D1.next
# find d2
D2 = self.head
while D2 is not None and D2.data != d2:
prevD2 = D2
D2 = D2.next
if D1 is None and D2 is None:
return
# if D1 is head
if prevD1 is not None:
prevD1.next = D2
else:
self.head = D2
# if D2 is head
if prevD2 is not None:
prevD2.next = D1
else:
self.head = D1
temp = D1.next
D1.next = D2.next
D2.next = temp
node_1 = self.head
while node_1 is not None and node_1.data != node_data_1:
node_1 = node_1.next

node_2 = self.head
while node_2 is not None and node_2.data != node_data_2:
node_2 = node_2.next

if node_1 is None or node_2 is None:
return

# swapping code ends here
node_1.data, node_2.data = node_2.data, node_1.data


if __name__ == "__main__":
list = Linkedlist()
list.push(5)
list.push(4)
list.push(3)
list.push(2)
list.push(1)
ll = LinkedList()
for i in range(5, 0, -1):
ll.push(i)

list.print_list()
ll.print_list()

list.swapNodes(1, 4)
ll.swap_nodes(1, 4)
print("After swapping")
list.print_list()
ll.print_list()