// class to combine ListNodes into a full linked list

public class LinkedIntList {
   private ListNode front;
   
   public LinkedIntList() {
      front = null;
   }
   
   // pre: num >= 0
   // create a list with integers from num to 0 in decending order
   //   e.g. 5 -> 5 - 4 - 3 - 2 - 1 - 0
   public LinkedIntList(int num) {
//       front = new ListNode(num);
//       
//       ListNode curr = front;
//       for (int i = num - 1; i >= 0; i--) {
//          ListNode temp = new ListNode(i);
//          curr.next = temp;
//          curr = curr.next;
//       }
      for (int i = 0; i <= num; i++) {
         ListNode temp = new ListNode(i, front);
         front = temp;
      }
   }
   
   public void add(int value) {
      if  (front == null) {
         // 1) change front
         front = new ListNode(value);
      } else {
         // find the last node
         ListNode curr = front;
         while (curr.next != null) {
            curr = curr.next;       
         }
         
         // attach a new node to the last node
         // 2) change the .next field of a node in the list
         ListNode temp = new ListNode(value);
         curr.next = temp;
      }
   }
   
   // pre: list is currently sorted in non-decreasing order
   public void addSorted(int value) {
      // cases:
      //   empty and front
      if (front == null || value < front.data) {
         ListNode temp = new ListNode(value, front);
         front = temp;
      } else {
         //   middle and end
         ListNode curr = front;
         while (curr.next != null && curr.next.data < value) {
            curr = curr.next;
         }
         ListNode temp = new ListNode(value, curr.next);
         curr.next = temp;
      }
   }
}