What the different between single and double linked list regarding space and operation?

Answer 1

Doubly linked lists require more memory than singly linked lists because each node in a doubly-linked list requires two pointers whereas each node in a singly-linked list only requires one pointer. In terms of operation, doubly-linked lists are only useful if you need bi-directional traversal of the the list. If you only need mono-directional traversal, a singly-linked list is more efficient. However, linked lists of either sort do not perform well when random access is essential. In this case a vector or an array will provide constant time access to any element, and memory consumption is further reduced since there is no longer a need for pointers. However, dynamic expansion of an array can be costly in terms of memory consumption and performance. In cases where random access and scalability are required, one or the other must be compromised.