Data Structure - Interview Questions and Answers for 'Data structure' | Search Interview Question

Interview Questions and Answers - Order By Newest

Q31. Which Data structure can be used for creating Queue ?

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve queue collections data structure}

Q32. Which of the two - Arrays or LinkedList - is a better data structure for implementing Queue ? and Why ?

Data Structure

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Arraylist linkedlist queue collections}

Q33. Write a program for binary tree ?

Data Structure

Ans. public class BinarySearchTree {
//Represent the node of binary tree
public static class Node {
int data;
Node left;
Node right;
public Node(int data) {
//Assign data to the new node, set left and right children to null

this.data = data;
this.left = null;
this.right = null;
}
}
//Represent the root of binary tree

public Node root;
public BinarySearchTree() {
root = null;
}

//factorial() will calculate the factorial of given number

public int factorial(int num) {
int fact = 1;
if (num == 0) return 1;
else {
while (num > 1) {
fact = fact * num;
num--;
}
return fact;
}
}

//numOfBST() will calculate the total number of possible BST by calculating Catalan Number for given key

public int numOfBST(int key) {
int catalanNumber = factorial(2 * key) / (factorial(key 1) * factorial(key));
return catalanNumber;
}
public static void main(String[] args) {
BinarySearchTree bt = new BinarySearchTree();

//Display total number of possible binary search tree with key 5

System.out.println("Total number of possible Binary Search Trees with given key: "
bt.numOfBST(5));
}
}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q34. Write an efficient program for printing k largest elements in an array. Elements in array can be in any order.

Data Structure

^{This question was recently asked at 'Amazon'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve arrays coding code Asked in 1 Companies}

Q35. What are the ways to get the values from list ?

Data Structure

Ans. list.get(index);

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve list Asked in 1 Companies}

Q36. Find Max from Stack in O(1) complexity

Algorithm

Ans. Create one extra field called MAX O(1)

when you an element to the stack check these two condition
1. Stack is empty, then MAX = element
2. Stack is not empty then check if the element is greater than MAX then MAX = element

when getMax fuction is called, then return MAX

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve complexity stack data structure Asked in 1 Companies}

Q37. How would you implement low latency data structures ?

Data Structure

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q38. Create a stack of specific size using arrayList?

Data Structure

Ans. public class StackUsingArrayList {
   public static void main(String[] args) {
      List list = new ArrayList();
      list.add("A");
      list.add("B");
      list.add("C");

      Stack stack = new Stack();

      list.forEach(a -> stack.add(a));
      System.out.println(stack);

   }
}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q39. How are hash codes generated ?

Data Structure

Ans. Use hashCode() which returns an integer value, generated by a hashing algorithm

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve hash codes hashcode Asked in 1 Companies}

Q40. Difference between Arrays and LinkedList ?

Data Structure

^{This question was recently asked at 'Spillman Technologies,Motorola Solutions'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 2 Companies}

Q41. Which of the following - arrays or LinkedList allow elements to be accessed using index and how ?

Data Structure

Ans. Arrays allows elements to be accessed directly using the index.

As Array elements are stored in continuous memory locations it's very easy to find the memory address of any element using the formula as following

Memory Address of Array start or index 0 + ( Size of array element * Index )

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve arrays linkedlist}

Q42. Can we access elements at a particular index using LinkedList collection class ?

Data Structure

Ans. Yes we can. But as the underlying structure of the collection class is double linked list, it will eventually have to traverse to the element linearlly and hence would result in bad performance.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q43. If a stack is implemented using an array, which end (head or tail) should represent the top ?

Data Structure

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q44. If a stack is implemented using linkedlist, which end (head or tail) should represent the top ?

Data Structure

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q45. Describe how a queue is usually created using sequential allocation.

Data Structure

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q46. What is the "multiplicative congruence" method for determining where an element belongs in a hash table ?

Data Structure

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q47. What is the access time for ArrayList and LinkedList ?

Data Structure

Ans. O(1) for ArrayList
O(n) for LinkedList

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 2 Companies}

Q48. Write a method that returns maximum depth of a tree ?

Algorithm

^{This question was recently asked at 'One Click Retail'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve tree data structure maximum depth of tree Asked in 1 Companies}

Q49. What can we do if we need to retrieve Fibonacci value at a particular index faster ? Can we use Linked List ?

Data Structure

^{This question was recently asked at 'Canopy Tax'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve LinkedList Asked in 1 Companies}

Q50. How will you implement your own custom hashmap and linkedlist ?

Data Structure

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q51. Why does an array index starts at 0 and not 1 ?

Data Structure

Ans. The array index starts with 0 because program locates an element using the expression ( BaseAddress + ( Index * size of array Element ), where index is used as an offset. As the starting address is actually the address of first element, the index of first element is used as 0 and so on.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q52. Why does an array need continuous memory locations and not Linked List ?

Data Structure

Ans. Array needs continuous memory location because it need to provide random access of it's elements which is not required for Linked List.

Array index acts as an offset from the base address and hence can retrieve the respective element using the expression Base Address + ( Index * Element Size ). This expression could only hold true if the elements are in continuous memory location.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q53. What is hashing ?

data structure

Ans. Hashing is a technique to calculate the hash code for any object

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q54. Can you write code to copy one array into another ?

Data Structure

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q55. Difference between Arrays and LinkedList ?

Data Structure

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve arrays vs linkedlist}

Q56. In an array every element is repeated twice except one, Find that element?

Data Structure

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q57. Find number of recycled pairs in n array.

Data Structure

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q58. Find the length of the non repeated numbers in an array.

Data Structure

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q59. Write a program to insert a value after a specific value in an array.

Data Structure

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q60. Write a Program to Find the maximum sum of the sub array ?

Data Structure

^{This question was recently asked at 'Reddit'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Maximum subarray variant arrays sub array subarray Asked in 1 Companies}

Search Interview Questions

Help us and Others Improve. Please let us know the questions asked in any of your previous interview.