Data Structure MCQ - Linked List
This section focuses on the "Linked List" of the Data Structure. These Multiple Choice Questions (mcq) should be practiced to improve the Data Structure skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
1. What does the following function do for a given Linked List with first node as head?
void fun1(struct node* head)
{
if(head == NULL)
return;
fun1(head->next);
printf("%d ", head->data);
}
A. Prints all nodes of linked lists
B. Prints all nodes of linked list in reverse order
C. Prints alternate nodes of Linked List
D. Prints alternate nodes in reverse order
View Answer
Ans : B
Explanation: fun1() prints the given Linked List in reverse manner. For Linked List 1->2->3->4->5, fun1() prints 5->4->3->2->1.
2. A linear collection of data elements where the linear node is given by means of pointer is called?
A. linked list
B. node list
C. primitive list
D. None of these
View Answer
Ans : A
Explanation: A linear collection of data elements where the linear node is given by means of pointer is called linked list.
3. What is the time complexity to count the number of elements in the linked list?
A. O(1)
B. O(n)
C. O(logn)
D. None of the mentioned
View Answer
Ans : B
Explanation: To count the number of elements, you have to traverse through the entire list, hence complexity is O(n).
4. What would be the asymptotic time complexity to add a node at the end of singly linked list, if the pointer is initially pointing to the head of the list?
A. O(1)
B. O(n)
C. θ (n)
D. θ (1)
View Answer
Ans : C
Explanation: No Explanation.
5. What is the output of following function for start pointing to first node of following linked list? 1->2->3->4->5->6
void fun(struct node* start)
{
if(start == NULL)
return;
printf("%d ", start->data);
if(start->next != NULL )
fun(start->next->next);
printf("%d ", start->data);
}
A. 1 4 6 6 4 1
B. 1 3 5 1 3 5
C. 1 2 3 5
D. 1 3 5 5 3 1
View Answer
Ans : D
Explanation:fun() prints alternate nodes of the given Linked List, first from head to end, and then from end to head. If Linked List has even number of nodes, then skips the last node.
6. What is the functionality of the following piece of code?
public int function(int data)
{
Node temp = head;
int var = 0;
while(temp != null)
{
if(temp.getData() == data)
{
return var;
}
var = var+1;
temp = temp.getNext();
}
return Integer.MIN_VALUE;
}
A. Find and delete a given element in the list
B. Find and return the given element in the list
C. Find and return the position of the given element in the list
D. Find and insert a new element in the list
View Answer
Ans : C
Explanation: When temp is equal to data, the position of data is returned.
7. Linked lists are not suitable to for the implementation of?
A. Insertion sort
B. Radix sort
C. Polynomial manipulation
D. Binary search
View Answer
Ans : D
Explanation: Linked lists are not suitable to for the implementation of Binary search.
8. In the worst case, the number of comparisons needed to search a singly linked list of length n for a given element is
A. log 2 n
B. n/2
C. log 2 n – 1
D. n
View Answer
Ans : D
Explanation: In the worst case, the element to be searched has to be compared with all elements of linked list.
9. Which of these is an application of linked lists?
A. To implement file systems
B. For separate chaining in hash-tables
C. To implement non-binary trees
D. All of the mentioned
View Answer
Ans : D
Explanation: Linked lists can be used to implement all of the above mentioned applications.
10. In circular linked list, insertion of node requires modification of?
A. One pointer
B. Two pointer
C. Three pointer
D. None
View Answer
Ans : B
Explanation: In circular linked list, insertion of node requires modification of Two pointer.
11. Consider an implementation of unsorted singly linked list. Suppose it has its representation with a head pointer only.
Given the representation, which of the following operation can be implemented in O(1) time?
i) Insertion at the front of the linked list
ii) Insertion at the end of the linked list
iii) Deletion of the front node of the linked list
iv) Deletion of the last node of the linked list
A. I and II
B. I and III
C. I, II and III
D. I, II and IV
View Answer
Ans : B
Explanation: None.
12. In linked list each node contain minimum of two fields. One field is data field to store the data second field is?
A. Pointer to character
B. Pointer to integer
C. Pointer to node
D. Node
View Answer
Ans : C
Explanation: None.
13. What would be the asymptotic time complexity to find an element in the linked list?
A. O(1)
B. O(n)
C. O(n2)
D. None of the mentioned
View Answer
Ans : B
Explanation: None.
14. The concatenation of two list can performed in O(1) time. Which of the following variation of linked list can be used?
A. Singly linked list
B. Doubly linked list
C. Circular doubly linked list
D. Array implementation of list
View Answer
Ans : C
Explanation: None.
15. Consider the following definition in c programming language.Which of the following c code is used to create new node?
struct node
{
int data;
struct node * next;
}
typedef struct node NODE;
NODE *ptr;
A. ptr = (NODE*)malloc(sizeof(NODE));
B. ptr = (NODE*)malloc(NODE);
C. ptr = (NODE*)malloc(sizeof(NODE*));
D. ptr = (NODE)malloc(sizeof(NODE));
View Answer
Ans :A
Explanation: As it represents the right way to create a node.
16. What kind of linked list is best to answer question like "What is the item at position n"?
A. Singly linked list
B. Doubly linked list
C. Circular linked list
D. Array implementation of linked list
View Answer
Ans : D
Explanation: None.
17. Linked lists are not suitable to for the implementation of?
A. Insertion sort
B. Radix sort
C. Polynomial manipulation
D. Binary search
View Answer
Ans : D
Explanation: It cannot be implemented using linked lists.
18. Linked list is considered as an example of ___________ type of memory allocation.
A. Dynamic
B. Static
C. Compile time
D. None of the mentioned
View Answer
Ans : A
Explanation: As memory is allocated at the run time.
19. In Linked List implementation, a node carries information regarding
A. Data
B. Link
C. Data and Link
D. None of the mentioned
View Answer
Ans : B
Explanation: None.
20. Linked list data structure offers considerable saving in
A. Computational Time
B. Space Utilization
C. Space Utilization and Computational Time
D. None of the mentioned
View Answer
Ans : C
Explanation: Linked lists saves both space and time.
21. Which of the following points is/are true about Linked List data structure when it is compared with array
A. Arrays have better cache locality that can make them better in terms of performance
B. It is easy to insert and delete elements in Linked List
C. Random access is not allowed in a typical implementation of Linked Lists
D. All of the mentioned
View Answer
Ans : D
Explanation: None.
22. Which of the following sorting algorithms can be used to sort a random linked list with minimum time complexity?
A. Insertion Sort
B. Quick Sort
C. Heap Sort
D. Merge Sort
View Answer
Ans : D
Explanation: Both Merge sort and Insertion sort can be used for linked lists. The slow random-access performance of a linked list makes other algorithms (such as quicksort) perform poorly, and others (such as heapsort) completely impossible. Since worst case time complexity of Merge Sort is O(nLogn) and Insertion sort is O(n2), merge sort is preferred.
23. Given pointer to a node X in a singly linked list. Only one pointer is given, pointer to head node is not given, can we delete the node X from given linked list?
A. Possible if X is not last node
B. Possible if size of linked list is even
C. Possible if size of linked list is odd
D. Possible if X is not first node
View Answer
Ans : A
Explanation:
Following are simple steps.
struct node *temp = X->next;
X->data = temp->data;
X->next = temp->next;
free(temp);
24. The following function reverse() is supposed to reverse a singly linked list. There is one line missing at the end of the function.What should be added in place of "/*ADD A STATEMENT HERE*/", so that the function correctly reverses a linked list.
struct node
{
int data;
struct node* next;
};
static void reverse(struct node** head_ref)
{
struct node* prev = NULL;
struct node* current = *head_ref;
struct node* next;
while (current != NULL)
{
next = current->next;
current->next = prev;
current = next;
}
/*ADD A STATEMENT HERE*/
}
A. *head_ref = prev;
B. *head_ref = current;
C. *head_ref = next;
D. *head_ref = NULL;
View Answer
Ans : A
Explanation: *head_ref = prev; At the end of while loop, the prev pointer points to the last node of original linked list.
We need to change *head_ref so that the head pointer now starts pointing to the last node.
25. he following C function takes a single-linked list of integers as a parameter and rearranges the elements of the list.
The function is called with the list containing the integers 1, 2, 3, 4, 5, 6, 7 in the given order. What will be the contents of the list after the function completes execution?
struct node
{
int value;
struct node *next;
};
void rearrange(struct node *list)
{
struct node *p, * q;
int temp;
if ((!list) || !list->next)
return;
p = list;
q = list->next;
while(q)
{
temp = p->value;
p->value = q->value;
q->value = temp;
p = q->next;
q = p?p->next:0;
}
}
A. 1, 2, 3, 4, 5, 6, 7
B. 2, 1, 4, 3, 6, 5, 7
C. 1, 3, 2, 5, 4, 7, 6
D. 2, 3, 4, 5, 6, 7, 1
View Answer
Ans : B
Explanation: The function rearrange() exchanges data of every node with its next node. It starts exchanging data from the first node itself.
Also Check :
Discussion