Add files via upload

Author: yadavrahulrao

linklist.py

@@ -0,0 +1,57 @@
+class ListNode:
+    def __init__(self, val=0, next=None):
+        self.val = val
+        self.next = next
+
+def reorderList(head: ListNode) -> None:
+    if not head or not head.next or not head.next.next:
+        return
+    slow, fast = head, head
+    while fast and fast.next:
+        slow = slow.next
+        fast = fast.next.next
+    second_half = slow.next
+    slow.next = None  
+    prev = None
+    while second_half:
+        next_node = second_half.next
+        second_half.next = prev
+        prev = second_half
+        second_half = next_node
+    first_half = head
+    second_half = prev 
+    
+    while second_half:
+      
+        temp1, temp2 = first_half.next, second_half.next
+        
+        
+        first_half.next = second_half
+        second_half.next = temp1
+        
+      
+        first_half = temp1
+        second_half = temp2
+
+def print_list(head: ListNode) -> None:
+    while head:
+        print(head.val, end=" -> " if head.next else "")
+        head = head.next
+    print()
+
+def create_linked_list(arr):
+    dummy = ListNode()
+    current = dummy
+    for val in arr:
+        current.next = ListNode(val)
+        current = current.next
+    return dummy.next
+
+head = create_linked_list([1, 2, 3, 4, 5, 6])
+print("Original List:")
+print_list(head)
+
+reorderList(head)
+
+print("Reordered List:")
+print_list(head)