
INFOSYS POWER PREPARATION
Data
Structures Questions
1. What is data structure?
A data structure is a way of organizing data
that considers not only the items stored,
but also their relationship to each other.
Advance knowledge about the relationship between
data items allows designing of efficient algorithms
for the manipulation of data.
2. List out the areas in which data structures
are applied extensively?
Ø Compiler Design,
Ø Operating System,
Ø Database Management System,
Ø Statistical analysis package,
Ø Numerical Analysis,
Ø Graphics,
Ø Artificial Intelligence,
Ø Simulation
3. What are the major data structures used
in the following areas : RDBMS, Network data
model & Hierarchical data model.
Ø RDBMS – Array (i.e. Array of structures)
Ø Network data model – Graph
Ø Hierarchical data model – Trees
4. If you are using C language to implement
the heterogeneous linked list, what pointer
type will you use?
The heterogeneous linked list contains different
data types in its nodes and we need a link,
pointer to connect them. It is not possible
to use ordinary pointers for this. So we go
for void pointer. Void pointer is capable
of storing pointer to any type as it is a
generic pointer type.
5. Minimum number of queues needed to implement
the priority queue?
Two. One queue is used for actual storing
of data and another for storing priorities.
6. What is the data structures used to perform
recursion?
Stack. Because of its LIFO (Last In First
Out) property it remembers its ‘caller’ so
knows whom to return when the function has
to return. Recursion makes use of system stack
for storing the return addresses of the function
calls.
Every recursive function has its equivalent
iterative (non-recursive) function. Even when
such equivalent iterative procedures are written,
explicit stack is to be used.
7. What are the notations used in Evaluation
of Arithmetic Expressions using prefix and
postfix forms?
Polish and Reverse Polish notations.
8. Convert the expression ((A + B) * C –
(D – E) ^ (F + G)) to equivalent Prefix and
Postfix notations.
Prefix Notation:
^ - * +ABC - DE + FG
Postfix Notation:
AB + C * DE - - FG + ^
9. Sorting is not possible by using which
of the following methods?
(a) Insertion
(b) Selection
(c) Exchange
(d) Deletion
(d) Deletion.
Using insertion we can perform insertion
sort, using selection we can perform selection
sort, using exchange we can perform the bubble
sort (and other similar sorting methods).
But no sorting method can be done just using
deletion.
10. A binary tree with 20 nodes has null
branches?
21
Let us take a tree with 5 nodes (n=5)
It will have only 6 (ie,5+1) null branches.
In general,
A binary tree with n nodes has exactly n+1
null nodes.
11. What are the methods available in storing
sequential files ?
Ø Straight merging,
Ø Natural merging,
Ø Polyphase sort,
Ø Distribution of Initial runs.
12. How many different trees are possible
with 10 nodes ?
1014
For example, consider a tree with 3 nodes(n=3),
it will have the maximum combination of 5
different (ie, 23 - 3 = 5) trees.
i ii iii iv v
In general:
If there are n nodes, there exist 2n-n different
trees.
13. List out few of the Application of tree
data-structure?
Ø The manipulation of Arithmetic expression,
Ø Symbol Table construction,
Ø Syntax analysis.
14. List out few of the applications that
make use of Multilinked Structures?
Ø Sparse matrix,
Ø Index generation.
15. In tree construction which is the suitable
efficient data structure?
(a) Array (b) Linked list (c) Stack (d)
Queue (e) none
(b) Linked list
16. What is the type of the algorithm used
in solving the 8 Queens problem?
Backtracking
17. In an AVL tree, at what condition the
balancing is to be done?
If the ‘pivotal value’ (or the ‘Height factor’)
is greater than 1 or less than –1.
18. What is the bucket size, when the overlapping
and collision occur at same time?
One. If there is only one entry possible
in the bucket, when the collision occurs,
there is no way to accommodate the colliding
value. This results in the overlapping of
values.