Let LIST be a datatype for an implementation of linked list defined as follows:

typedef struct list {
    int data;
    struct list *next;
} LIST;

Suppose a program has created two linked lists, L1 and L2, whose contents are given in the figure below (code for creating L1 and L2 is not provided here). L1 contains 9 nodes, and L2 contains 7 nodes. Consider the following C program segment that modifies the list L1. The number of nodes that will be there in L1 after the execution of the code segment is _________. (Answer in integer)

A queue is implemented using a non-circular singly linked list. The queue has a head pointer and a tail pointer, as shown in the figure. Let $$n$$ denote the number of nodes in the queue. Let $$enqueue$$ be implemented by inserting a new node at the head, and $$dequeue$$ be implemented by deletion of a node from the tail.

Which one of the following is the time complexity of the most time-efficient implementation of $$enqueue$$ and $$dequeue,$$ respectively, for this data structure?

The preorder traversal sequence of a binary search tree is 30, 20, 10, 15, 25, 23, 39, 35, 42. Which one of the following is the postorder traversal sequence of the same tree?

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.

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; 
} 

Choose the correct alternative to replace the blank line.