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