Data Structure interview questions

When is insertion sort a good choice for sorting an array?

1. The array has only a few elements out of place
2. Each element of array requires a small amount of memory
3. The processor speed is fast
4. Each element of array requires a large amount of memory

A binary tree in which all its levels except the last, have maximum numbers of nodes, and all the nodes in the last level have only one child it will be its left child. Name the tree.

1. Threaded tree
2. Complete binary tree
3. M-way search tree
4. Full binary tree

Which of following data structure is more appropriate for implementing quick sort iteratively?

1. Deque
2. Queue
3. Stack
4. Priority queue

The number of edges in a complete graph of n vertices is

1. n(n+1)/2
2. n(n-1)/2
3. n2/2
4. n

If two trees have same structure and but different node content, then they are called ___

1. Synonyms trees
2. Joint trees
3. Equivalent trees
4. Similar trees

If two trees have same structure and node content, then they are called ____

1. Synonyms trees
2. Joint trees
3. Equivalent trees
4. Similar trees

A vertex of in-degree zero in a directed graph is called a/an

1. Root vertex
2. Isolated vertex
3. Sink
4. Articulation point

A graph is a tree if and only if graph is

1. Directed graph
2. Contains no cycles
3. Planar
4. Completely connected

An index is a pair of elements comprising key and a file pointer or record number. A file in which indices are is known as ____

1. Index file
2. Sort file
3. Key file
4. None of above

A data item that can be used to distinguish between two entities (records) is known as

1. Alternate key
2. Primary key
3. Primary data item
4. Unique data item

A data structure whose elements form a sequence is known as

1. Heterogeneous data structure
2. Homogeneous data structure
3. Linear data structures
4. Non- linear data structure

Which of the following data structure is used to represent hierarchical relationship among its elements?

1. Queue
2. Hash table
3. Tree
4. Graph

Which of the following statements about a binary tree is not correct?

1. Every binary tree has at least one node
2. Every non-empty tree has exactly one root node
3. Every node has at most two children
4. Every non-root node has exactly one parent

The average case complexity of quick sort for sorting n numbers is

1. O(n2)
2. O(nlog2n)
3. O(n)
4. O(log2n)

A dequeue operation removes an element

1. From the front of the queue
2. From any place in the queue
3. From the rear of the queue
4. None of above

What is the minimum number of nodes in a complete binary tree with depth 3?

1. 4
2. 5
3. 6
4. 7

What is the number of nodes in a full binary tree with depth 3?

1. 5
2. 6
3. 7
4. 8

Which of the following operation is not supported by a queue?

1. Inserting element at rear
2. Removing element from front
3. Removing element from middle
4. None of above

Which of the following piece of information does the data type to the compiler provide?

1. The way the data is to be interpreted
2. Range of values
3. Amount of memory a data element uses
4. All of above

The elements of a linked list are stored

1. In a structure
2. In an array
3. Anywhere the computer has space for them
4. In contiguous memory locations

A parentheses checker program would be best implemented using

1. List
2. Queue
3. Stack
4. Any of the above

To perform level-order traversal on a binary tree, which of the following data structure will be required?

1. Hash table
2. Queue
3. Binary search tree
4. Stack

Which of the following data structure is required to convert arithmetic expression in infix to its equivalent postfix notation?

1. Queue
2. Linked list
3. Binary search tree
4. None of above

An enqueue operation adds an element

1. At any position in the queue
2. To the front of the queue
3. To the rear of the queue
4. None of above

Which of the following is not an entity?

1. Book
2. Student
3. Employee
4. Roll number

What kind of list is best to answer many questions such as “what is the item at position n?”

1. Singly-linked lists
2. Doubly-linked lists
3. Lists implemented with an array
4. Circular- linked lists

Which of following operations are generally not performed on report files?

1. Updation
2. Maintenance
3. Retrieval
4. All of above

Name the tree in which, for every node, the height of left sub tree and height of right sub tree can differ by at most one

1. AVL tree
2. B-tree
3. Threaded tree
4. Complete tree

Which of the following statements about a binary tree is correct?

1. No binary tree is both complete and full
2. Every full binary tree is also a complete binary tree
3. Every complete binary tree is also a full binary tree
4. Every binary tree is either complete or full

What is the worst-case time for binary search finding a single item in an array?

1. Quadratic time
2. Linear time
3. Logarithmic time
4. Constant time