**top most important questions**and

**answers**about the

**Data Structures and algorithms**. so if you are preparing for the

**competitive exams**, or for

**coding interviews**for

**big companies**like

**Google, Microsoft, Amazon**, etc then you must prepare for the

**Data structures and algorithms questions**. so here we are including some

**basic**to

**advanced questions**related to

**DSA**so you can prepare for this topic.

#### Consider the following tree

- +,-,*,a,b,c,d
- a,-,b,+,*,d
- a,b,c,d,d,-,*,+
- -,a,b,+,*,c,d

**Answer - (1) +,-,*,a,b,c,d**

#### Consider the following tree

If this tree is used for sorting, then a new number 8 should be placed as the

- the left child of the node labeled 30
- right child of the node labeled 5
- right child of the node labeled 30
- the left child of the node labeled 10

**Answer - (4) the left child of the node labeled 10**

#### The initial configuration of a queue is a,b,c,d,('a' is in the front end). To get the configuration d,c,b, a, one needs a minimum of

- 2 deletions and 3 additions
- 3 deletions and 2 additions
- 3 deletions and 3 additions
- 3 deletions and 4 additions

**Answer - (3) 3 deletions and 2 additions**

#### The order of a B-tree is defined as the

- Minimum no. of keys in a non-root node
- Maximum no. of keys in a non-root node
- (n + 1) / 2
- Maximum no. of pointers in any node

**Answer - (4) Maximum no. of pointers in any node**

#### If the sequence of operations - push(1), push(2), pop, push(1), push(20), pop, pop, pop, push(2), pop, are performad on a stack, the sequence of popped out values are

- 2,2,1,1,2
- 2,2,1,2,2
- 2,1,2,2,1
- 2,1,2,2,2

**Answer - (1) 2, 2, 1, 1, 2**

#### The depth of a complete binary tree with 'n' nodes is (log is to the base two)

- log(n + 1) - 1
- log(n)
- log(n - 1) + 1
- log(n) + 1

**Answer - (1) log(n + 1) - 1**

#### Preorder is same as

- depth-first order
- breadth-first order
- topological order
- linear order

**Answer - (1) depth-first order**

#### Which of the following traversal techniques lists the nodes of a binary search tree in ascending order?

- Post-order
- In-order
- Pre-order
- None of the above

**Answer - (2) In-order**

#### A hash function f defined as f(key) = key mod 7, with linear probing, is used to insert the keys 37,38,72,48,98,11,56, into a table indexed from 0 to 6. What will be the location of key 11?

- 3
- 4
- 5
- 6

**Answer - (3) 5**

#### There are 4 different algorithms A1,A2,A3,A4 to solve a given problem with the order log(n), log(log(n)), nlog(n), n/logn respectively. Which is the best algorithm?

- A1
- A2
- A4
- A3

**Answer - (2) A2**

#### The number of possible binary search trees with 3 nodes is

- 12
- 13
- 5
- 15

**Answer - (3) 5**

#### Sorting is useful for

- report generation
- minimizing the storage needs and responding to queries easily
- making searching easier and more efficient
- all of the above

**Answer - (4) all of the above**

#### The order of an algorithm that finds whether a given Boolean function of 'n' variables, produces a 1 is

- constant
- linear
- logarithmic
- exponential

**Answer - ( 4) exponential**

In evaluating the arithmetic expression 2 * 3 - (4 + 5), using stacks to evaluate its equivalent postfix form, which of the following stack configuration is not possible?

**Answer - (d)**

#### The way a card game player arranges his cards as he picks them up one by one is an example of

- bubble sort
- selection sort
- insertion sort
- merge sort

**Answer - (3) insertion sort**

#### You want to check whether a given set of items is sorted. Which of the following sorting methods will be the most efficient if it is already in sorted order?

- Bubble sort
- Selection sort
- Insertion sort
- Merge sort

**Answer - (3) insertion sort**

#### Which of the following sorting methods will be the best if a number of swappings is done, is the only measure of efficiency?

- bubble sort
- selection sort
- insertion sort
- Quicksort

**Answer - (3) insertion sort**

#### You are asked to sort 15 randomly generated numbers. You should prefer

- bubble sort
- selection sort
- insertion sort
- Quicksort

**Answer - (3) insertion sort**

#### As part of maintenance work, you are entrusted with the work of rearranging the library books on a shelf in proper order, at the end of each day. The ideal choice will be

- bubble sort
- selection sort
- insertion sort
- heap sort

**Answer - (2) selection sort**

#### Which of the following algorithms exhibits the unnatural behavior that, the minimum number of comparisons are needed if the list to be sorted is in the reverse order and a maximum number of comparisons are needed if they are already in sorted order?

- Heapsort
- Radix sort
- Binary insertion sort
- There can't be any such sorting methods

**Answer - (3) Binary insertion sort**

Note - more questions and answers will be added from time to time.

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