# function for reversing the linked lists
def reverse_stack(head):
stack = []
ptr = head
# pushing into stack till all elements of type Node is pushed
while (ptr.next):
stack.append(ptr)
ptr = ptr.next
# then, we make last element as head of new list
head = ptr
# keep popping till stack is empty and all elements are appended to the end of new list whose head is the actual last element of original list , so maybe we are taking extra space for creating new pointers, but also after exhausting stack, those original pointers are being deleted by python compiler, thereby it is not much big issue.
# But space taken by stack is of some issue when lists are much big.
while (stack):
ptr.next = stack.pop()
ptr = ptr.next
ptr.next = None
return head
if __name__ == '__main__':
s = Stack()
s.push(0)
s.push(1)
s.push(2)
s.push(3)
head = s.getTop()
head = reverse_stack(head)
print(head.data)
