Question

Write a routine to interchange the mth and nth elements of a singly-linked list. You may assume that the ranks m and n are passed in as parameters. Allow for all the ways that m and n can occur. You must rearrange the pointers, not simply swap the contents.

Answer 1

//The routine to swap m th and nth ranked elements

void swapmAndn(int m, int n)

{

//Set the linked list head node

Linked_Node **node_head

//To find the m ranked node

//set previous node

Linked_Node *node_prev = NULL;

//set node to store m ranked node as head node

Linked_Node *node_current_m = *node_head;

//set the rank as rm=1

rm =1

//traverse to find the m ranked node

while (node_current_m && rm<m)

{

node_prev = node_current_m;

node_current_m = node_current_m->next;

rm++;

}

//To find the n ranked node

//set previous node

Linked_Node *node_prev_n = NULL;

//set node to store n ranked node as head node

Linked_Node *node_current_n = *node_head;

//set the rank as rn=1

rn =1

//traverse to find the n ranked node

while (node_current_n && rn<n)

{

node_prev_n= node_current_n;

node_current_n = node_current_n->next;

rn++;

}

//if m is not first ranked node

if (node_prev != NULL)

//set node_current_n as previous node

node_prev->next = node_current_n;

//otherwise Set the node_current_n

else

*node_head = node_current_n;

// If n is not first ranked node

if (node_prev_n!= NULL)

node_prev_n->next = node_current_m;

else

*node_head = node_current_m;

//now swap the next pointers also

//to make the swap process complete

Linked_Node *temp = node_current_n->next;

node_current_n->next = node_current_m->next;

node_current_m->next = temp;

}

Step-by-step explanation: