data structures important questions
Q 1. what is a data- structure?
ans. a data – structure is a logical way for organizing data in memory that considers not only the items stored but also the relationship among the items so as to give efficient and optimal performance . in other words , it is a organizing data such that it can be used efficiently.
Q 2. write the equivalent infix expression for : 10,3,*,7,1,-,*,23,+
Q 3. write the equivalent infix expression for given post-fix expression : a,b,AND,a,c,AND,OR.
ans. a AND b OR a AND c.
Q 4. what is a stack?
ans. a stack is a linear list implemented in LIFO- Last In First Out manner where insertions and deletions are restricted to occur only at one end – stack’s top.
Q 5. enlist some applications of stacks.
ans. because of LIFO property of stacks, these are used in various applications like:
(i) reversal of a sequence,
(ii)infix to post-fix conversion,
(iii) post-fix and prefix expression evaluation,
and many more.
Q 6. what is a queue?
ans. a queue is a linear list implemented in FIFO – First In First Out manner where insertions take place at the rear- end and deletions are restricted to occur only at front end of the queue.
Q 7. enlist some applications of queues.
ans. applications of queues include the situations where FIFO property is exploited . some common applications of queues include:
(i) sharing of one resource among multiple users or seekers such as shared printer among multiple computers; call center executive’s response among waiting callers etc.
(ii) airport authorities make use of queues in situation of sharing a single runway of airport for both landing and take – off of flights .
(iii) CPU uses queues to implement round-robin scheduling among waiting processes.
(iv) Queues are used in many computer algorithms also.
Q 8. which data structure will you use for simulating a blanket donation camp?
ans. a queues.
Q 9. given a stack as an array of 7 elements STACK :K,P,S,-,-,-,
(a) when will overflow and underflow occur?
(b) can K be deleted before S ? why?
ans. (a) overflow will occur when stack will be having 7 elements and there would be no space to insert a new element.
underflow will occur when all the elements will have been deleted from the stack and no more element could be deleted.
(b) K can not be deleted before S. as S has been inserted after K and stack follows the LIFO rule i.e., Last In First Out , therefore S will be deleted before K.
Q 12. consider an empty stack of integer.let the numbers 1,2,3,4,5,6 be pushed on to this stack only in the order they appeared from left to right. let S indicate a push and X indicates a pop operation.can they be outputted into the order 325641 and order 154623.
(hint. SSSSSSXXXXXX outputs 654321)
ans. SSSXXSSXSXXX outputs 325641.
154623 cannot be output as 2 is pushed much before 3 so can appear only after 3 in output.