# Skip List | Data Structure MCQs

1.

The nodes in a skip list may have many forward references. their number is determined

A.) probabilistically
B.) sequentially
C.) randomly
D.) orthogonally

The number of forward references are determined probabilistically, that is why skip list is a probabilistic algorithm.

2.

What is indexed skip list?

A.) it stores width of link in place of element
B.) it stores index values
D.) indexed tree

The width is defined as number of bottom layer links that are being traversed by each of higher layer elements. e.g: for a level-2 skip lists, all level-1 nodes have 1 as width, for level-2 width will be 2.

3.

What is the time complexity improvement of skip lists from linked lists in insertion and deletion?

A.) O(n) to O(logn) where n is number of elements
B.) O(n) to O(1) where n is number of elements
C.) no change
D.) O(n) to O(n2) where n is number of elements

O(n) to O(logn) where n is number of elements

4.

What is a skip list?

A.) a linkedlist with size value in nodes
B.) a linkedlist that allows faster search within an ordered sequence
C.) a linkedlist that allows slower search within an ordered sequence
D.) a tree which is in the form of linked list

It is a datastructure, which can make search in sorted linked list faster in the same way as binary search tree and sorted array (using binary search) are faster.

5.

To which datastructure are skip lists similar to in terms of time complexities in worst and best cases?

A.) balanced binary search trees
B.) binary search trees
C.) binary trees

Skip lists are similar to any randomly built binary search tree. a BST is balanced because to avoid skew tree formations in case of sequential input and hence achieve O(logn) in all 3 cases. now skip lists can gurantee that O(logn) complexity for any input.

6.

How to maintain multi-level skip list properties when insertions and deletions are done?

A.) design each level of a multi-level skip list with varied probabilities
B.) that cannot be maintained
C.) rebalancing of lists
D.) reconstruction

for example consider a 2 level skip list. the level-2 skip list can skip one node on a average and at some places may skip 2 nodes, depending on probabilities. this ensures O(logn).

7.

Skip lists are similar to which of the following datastructure?

A.) heap
B.) balanced binary search tree
C.) stack
D.) binary search tree