Data structure Interview Questions and Answers
Question - 71 : - Define what is an array?
Answer - 71 : -
While referring to array the data is stored and utilized based on the index and this number actually co-relates to the element number in the data sequence. So thus making it flexible to access data in any order. Within programming language, an array is considered as a variable having a certain number of indexed elements.
Question - 72 : - Can you tell me the minimum number of queues that are needed to implement a priority queue?
Answer - 72 : -
The minimum number of queues that are needed is two. Out of which, one queue is intended for sorting priorities and the other queue is meant for the actual storage of data.
Question - 73 : - List out all different sorting algorithms that are available and state which sorting algorithm is considered as the fastest?
Answer - 73 : -
The list of all sorting algorithms are below:
- Quicksort
- Bubble sort
- Balloon sort
- Radix sort
- Merge sort
Out of the above sorting options, none of the sorting algorithms can be tagged as the fastest algorithm, because each of these sorting algorithms is defined for a specific purpose. So based on the data structure and data sets available the sorting algorithms are used.
Question - 74 : - Explain what is a dequeue?
Answer - 74 : -
A de queue is nothing but a double-ended queue. Within this structure, the elements can be inserted or deleted from both sides.
Question - 75 : - Explain the process of how a selection sort works?
Answer - 75 : -
A selection sort is a process where it picks up the smallest number from the entire data setlist and places it at the beginning. The same process is continued where the second position is already filled in. The same process is continued all the way until the list is completed. The selection sort is defined as a simple sort algorithm when compared to others.
Question - 76 : - Explain what is a graph?
Answer - 76 : -
A graph is nothing but a type of data structure that has a set of ordered pairs. In turn, these pairs are again acknowledged as edges or arcs. These are used to connect different nodes where the data can be accessed and stored based on the needs.
Question - 77 : - Is it possible to implement a stack using a queue?
Answer - 77 : -
Yes, you can implement a stack using two queues. Any data structure to act like a stack should have a push() method to add data on top and a pop() method to remove the top data.
Question - 78 : - How would you implement a queue using a stack?
Answer - 78 : -
Using two stacks, you can implement a queue. The purpose is to complete the queue's en queue operation so that the initially entered element always ends up at the top of the stack.
- First, to enqueue an item into the queue, migrate all the elements from the beginning stack to the second stack, push the item into the stack, and send all elements back to the first stack.
- To dequeue an item from the queue, return the top item from the first stack.
Question - 79 : - Where is the LRU cache used in data structure?
Answer - 79 : -
In data structures, you use LRU (Least Recently Used) cache to organize items in order of use, enabling you to quickly find out which item hasn't been used for a long time.
Question - 80 : - Which data structures do you use in DFS and BFS algorithms?
Answer - 80 : -
- In the DFS algorithm, you use the Stack data structure.
- In the BFS algorithm, you use the Queue data structure.