HI
I have a question about second solution in this problem " Convert Binary Tree to Doubly Linked List".
The way which fused two sorted double link confused me.
def concatenate_lists(head1, head2):
if head1 is None:
return head2
if head2 is None:
return head1
# use left for previous.
# use right for next.
tail1 = head1.left
tail2 = head2.left
tail1.right = head2
head2.left = tail1
head1.left = tail2
tail2.right = head1
return head1
Could you help me explain that why
head1.left = tail2
tail2.right = head1
Thanks