Q. Consider the following function that takes reference to head of a Doubly Linked List as parameter. Assume that a node of doubly linked list has previous pointer as prev and next pointer as next.

void fun(struct node **head_ref)
{
struct node *temp = NULL;
struct node *current = *head_ref;

while (current != NULL)
{
temp = current->prev;
current->prev = current->next;
current->next = temp;
current = current->prev;
}

if(temp != NULL )
*head_ref = temp->prev;
}

Assume that reference of head of following doubly linked list is passed to above function 1 <--> 2 <--> 3 <--> 4 <--> 5 <-->6. What should be the modified linked list after the function call?

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Q. Which of the following sorting algorithms can be used to sort a random linked list with minimum time complexity?

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Q. The following function reverse() is supposed to reverse a singly linked list. There is one line missing at the end of the function.

/* Link list node */
struct node
{
    int data;
    struct node* next;
};
 
/* head_ref is a double pointer which points to head (or start) pointer
  of linked list */
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;  
        prev = current;
        current = next;
    }
    /*ADD A STATEMENT HERE*/
}

What should be added in place of "/*ADD A STATEMENT HERE*/", so that the function correctly reverses a linked list.

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Q. 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);
}

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Q. The following C function takes a simply-linked list as input argument. It modifies the list by moving the last element to the front of the list and returns the modified list. Some part of the code is left blank. Choose the correct alternative to replace the blank line.
typedef struct node
{
  int value;
  struct node *next;
}Node;
  
Node *move_to_front(Node *head)
{
  Node *p, *q;
  if ((head == NULL: || (head->next == NULL))
    return head;
  q = NULL; p = head;
  while (p-> next !=NULL)
  {
    q = p;
    p = p->next;
  }
  _______________________________
  return head;
}

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Q. The 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;
  }
}

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Q. In the worst case, the number of comparisons needed to search a singly linked list of length n for a given element is

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Q. Suppose each set is represented as a linked list with elements in arbitrary order. Which of the operations among union, intersection, membership, cardinality will be the slowest?

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Q. Consider the function f defined below.

struct item
{
int data;
struct item * next;
};

int f(struct item *p)
{
return (
(p == NULL) ||
(p->next == NULL) ||
(( P->data <= p->next->data) && f(p->next))
);
}

For a given linked list p, the function f returns 1 if and only if

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Q. What are the time complexities of finding 8th element from beginning and 8th element from end in a singly linked list? Let n be the number of nodes in linked list, you may assume that n > 8.

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Q. Is it possible to create a doubly linked list using only one pointer with every node.

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Q. 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?

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Q. You are given pointers to first and last nodes of a singly linked list, which of the following operations are dependent on the length of the linked list?

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Q. Consider the following function to traverse a linked list.

void traverse(struct Node *head)
{
while (head->next != NULL)
{
printf("%d ", head->data);
head = head->next;
}
}

Which of the following is FALSE about above function?

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Q. Let P be a singly linked list. Let Q be the pointer to an intermediate node x in the list. What is the worst-case time complexity of the best known algorithm to delete the node x from the list?

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Q. N items are stored in a sorted doubly linked list. For a delete operation, a pointer is provided to the record to be deleted. For a decrease-key operation, a pointer is provided to the record on which the operation is to be performed. An algorithm performs the following operations on the list in this order: Θ(N) delete, O(log N) insert, O(log N) find, and Θ(N) decrease-key What is the time complexity of all these operations put together

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Q. Following is C like pseudo code of a function that takes a number as an argument, and uses a stack S to do processing.

void fun(int n)
{
Stack S; // Say it creates an empty stack S
while (n > 0)
{
// This line pushes the value of n%2 to stack S
push(&S, n%2);

n = n/2;
}

// Run while Stack S is not empty
while (!isEmpty(&S))
printf("%d ", pop(&S)); // pop an element from S and print it
}

What does the above function do in general?

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Q. Which one of the following is an application of Stack Data Structure?

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Q. Which of the following is true about linked list implementation of stack?

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Q. Consider the following pseudo code that uses a stack

declare a stack of characters
while ( there are more characters in the word to read )
{
   read a character
   push the character on the stack
}
while ( the stack is not empty )
{
   pop a character off the stack
   write the character to the screen
}

What is output for input "computersciencebits"?

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