Friday, 21 September 2012

DS Interview Questions-3


31. What are the major data structures used in the following areas : network data model & Hierarchical data model.
Ans:
RDBMS – Array (i.e. Array of structures)
Network data model – Graph
Hierarchical data model – Trees

32. If you are using C language to implement the heterogeneous linked list, what pointer type will you use?
Ans: 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.

33. Minimum number of queues needed to implement the priority queue?
Ans: Two. One queue is used for actual storing of data and another for storing priorities.

34. What is the data structures used to perform recursion?
Ans: 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.

35. What are the notations used in Evaluation of Arithmetic Expressions using prefix and postfix forms?
Ans: Polish and Reverse Polish notations.

36. Convert the expression ((A + B) * C – (D – E) ^ (F + G)) to equivalent Prefix and Postfix notations.
Ans: Prefix Notation:
^ – * +ABC – DE + FG
Postfix Notation:
AB + C * DE – – FG + ^

37. Sorting is not possible by using which of the following methods?
(a) Insertion
(b) Selection
(c) Exchange
(d) Deletion
Ans: (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.

38. List out few of the Application of tree data-structure?
Ans:
The manipulation of Arithmetic expression.
Symbol Table construction.
Syntax analysis.

39. List out few of the applications that make use of Multilinked Structures?
Ans: Sparse matrix, Index generation.

40. In tree construction which is the suitable efficient data structure?
(A) Array (b) Linked list (c) Stack (d) Queue (e) none
Ans: (b) Linked list

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