Question

This is based on LinkedLists. Please complete the methods max() and threshold(). I'd greatly appreciate it. There is a type mismatch in my first method and I dont know how to get around it. I've commented on the line with the type mismatch. Please write a correct method in the answer so I can compare it to my wrong method

public class Node {
   public T info;
public Node link;
public Node(T i, Node l) {
   info = i; link = l;
   }
}

class LinkedList> {
  
protected Node head = null;
public LinkedList add(T el) {
head = new Node(el, head);
return this;
}
public void print() {
for(Node node = head; node!=null; node=node.link) {
System.out.print(node.info+" ");
}
System.out.println("");
}
  
public T maxValue() { // Note: Recursive methods not allowed, using new key word not allowed, no iterators allowed
   if (head == null) {
   return null;
   }
   else {
   Node temp = head;
   if (temp.link == null) {
   return temp.info;
   }
   else {
   T max = temp.link; //type mismatch
   if (temp.info.compareTo(max) > 0)
   max = temp.info;
   return max;
   }
}
}
  
public void threshold(T thres) {//Note: Recursive methods not allowed, using new key word not allowed, no iterators allowed

}

public static void main(String args[]) {
  
LinkedList list = new LinkedList();
System.out.println(list.maxValue()); // should be null
list.add(20).add(30).add(10);
System.out.println(list.maxValue()); // should be 30
list.threshold(40);
list.print(); // should print out all elements
list.threshold(30);
list.print(); // should print out 10 20
list.threshold(10);
list.print(); // should print nothing
}
}

Answer 1

class Structure<T> {
        public T info;
        public Structure<T> link;
        public Structure(T i, Structure<T> l) {
           info = i; link = l;
        }
}

public class LinkedList<T> {
          
        protected Structure<T> head = null;                       
        public LinkedList<T> add(T el) {
                head = new Structure<T>(el, head);
                return this;
        }
        public void print() {
                for(Structure structure = head; structure!=null; structure=structure.link) {
                System.out.print(structure.info+" ");
        }
        System.out.println("");
        }
        /*
         * It is your maxValue function
         */
        public T maxValue() { // Note: Recursive methods not allowed, using new key word not allowed, no iterators allowed
           /*
            * Base critera to return when Linked list is empty
            */
                if (head == null) {
                   return null;
           }
                /*
                 * If single node is there then node itself is highest..
                 */
           else {
                   Structure temp = head;
                   if (temp.link == null) {
                   return (T) temp.info;
           }
           else {
                   /*
                    * We get the value of current info
                    */
                   T max = (T) temp.info;
                   /*
                    * This method is used get datatype and for each datatype we have to apply our 
                    * equality condition
                    * In each case we compare the ax value with the current value if current value is max then 
                    * replace them
                    */
                   
                   
                   String x = max.getClass().getName();
                   while(temp.link!=null) {
                           if(x.equalsIgnoreCase("java.lang.String")) {
                                   if (((String) temp.info).compareTo((String) max) > 0)
                                           max = (T) temp.info;
                                   }
                           else if(x.equals("java.lang.Integer")) {
                                   if((int)temp.info>(int)max)
                                           max=(T) temp.info;
                                        }
                           else if(x.equalsIgnoreCase("java.lang.Double")) 
                                   {
                                   if((double)temp.info>(double)max)
                                   max=(T) temp.info;
                                   }
                           else if(x.equalsIgnoreCase("java.lang.Character")) 
                                   {
                                   if((char)temp.info>(char)max)
                                   max=(T) temp.info;
                                   }
                                   temp=temp.link;
           }
                         
           return max;
           }
        }
        }
          
        public void threshold(T thres) {//Note: Recursive methods not allowed, using new key word not allowed, no iterators allowed
                if (head == null) {
                           return ;
                   }
                /*
                 * Take two references of tye structure inititalise each from head
                 *First is base condition when Linked List is empty
                 *Secondly if first element is thres then break the entire codition(requirement not clear)
                 *
                 */
                Structure<T> temp=head;
                Structure<T> ptr=head;
                if(head==null)
                        return;
                else if(head.info==thres) {
                        head=null;
                }
                /*
                 * In this logic I've created a while loop which continues till we found the thres or link is null
                 * if data is not present and we reached to last node then return
                 * else 
                 * take ptr and traverse through just previous node of the temp node.
                 * then change the address part to remove an element.
                 */
                else {
                        while(temp.link!=null && temp.info!=thres) {
                                temp=temp.link;
                        }
                        if(temp.link==null && temp.info!=thres) {
                                return;
                        }
                        while(ptr.link!=temp) {
                                ptr=ptr.link;
                        }
                        
                        ptr.link=temp.link;
                        
                }
        }

        public static void main(String args[]) {
          
        LinkedList list = new LinkedList();
                System.out.println(list.maxValue()); // should be null
                list.add(20).add(30).add(10);
                System.out.println(list.maxValue()); // should be 30
                list.threshold(40);     
                list.print(); // should print out all elements
                list.threshold(30);
                list.print(); // should print out 10 20
                list.threshold(10);
                list.print(); // should print nothing
                }
        }

Hope You like the solution the explaination is attached with the documentation itself. One requirement is not so cleared bu I created my logic from the example. Hope you like the solution If you do so then support us by pressing that upvote button.