Tough explanation please

Code of Merge sort

************* template void unorderedLinkedList:: divideList(nodeType* first1, nodeType* &first2) { nodeType* middle; nodeType* current; if (first1 == NULL) //list is empty first2 = NULL; else if (first1->link == NULL) //list has only one node first2 = NULL; else { middle = first1; current = first1->link; if (current != NULL) //list has more than two nodes current = current->link; while (current != NULL) { middle = middle->link; current = current->link; if (current != NULL) current = current->link; } //end while first2 = middle->link; //first2 points to the first /ode of the second sublist middle->link = NULL; //set the link of the last node //of the first sublist to NULL } //end else } //end divideList template nodeType* unorderedLinkedList:: mergeList(nodeType* first1, nodeType* first2) { nodeType *lastSmall; //pointer to the last node of //the merged list nodeType *newHead; //pointer to the merged list if (first1 == NULL) //the first sublist is empty return first2; else if (first2 == NULL) //the second sublist is empty return first1; else { if (first1->info info) //compare the first nodes { newHead = first1; first1 = first1->link; lastSmall = newHead; } else { newHead = first2; first2 = first2->link; lastSmall = newHead; } while (first1 != NULL && first2 != NULL) { if (first1->info info) { lastSmall->link = first1; lastSmall = lastSmall->link; first1 = first1->link; } else { lastSmall->link = first2; lastSmall = lastSmall->link; first2 = first2->link; } } //end while if (first1 == NULL) //first sublist is exhausted first lastSmall->link = first2; else //second sublist is exhausted first lastSmall->link = first1; return newHead; } }//end mergeList template void unorderedLinkedList::recMergeSort(nodeType* &head) { nodeType *otherHead; if (head != NULL) //if the list is not empty if (head->link != NULL) //if the list has more than one node { divideList(head, otherHead); recMergeSort(head); recMergeSort(otherHead); head = mergeList(head, otherHead); } } //end recMergeSort template void unorderedLinkedList::mergeSort() { recMergeSort(first); if (first == NULL) last = NULL; else { last = first; while (last->link != NULL) last = last->link; } } //end mergeSort

Given the linked list in Figure 11 and the merge sort algorithm the total number of divide list and merge list steps to sort this list is TDDIDATHE THAIL head Figure-11 Select one 6. 6 steps 12 steps Ste