public class LinkedList3 { private Node head = null; public class Node { char data; Node next; Node(char c) { data = c; } } build these 3 methods in java language public int countOccurencesOf(char c) { int count = 0; return count; }  public char getLast() { } public void deleteLast() { }

Complete public class Solution {           public static LinkedListNode<Integer> findPrevNode(LinkedListNode<Integer> head, int count)   {   for (int i=0;i<count-1;i++)   {   head=head.next;   }   return head;   }       public static LinkedListNode<Integer> swapNodes(LinkedListNode<Integer> head, int i, int j) {   //Your code goes here   if (head==null)   {   return head;   }   else if (j==0 || (i-j==-1))   {   int temp=i;   i=j;   j=temp;   }       LinkedListNode<Integer> swap1=null,swap2=null,p1=null,n1=null,p2=null,n2=null;       if (i==0 && i-j==1)   {   swap1=head;   swap2=head.next;       swap1=swap1.next;   head=swap2;   swap2.next=swap1;       }   else if(i-j==1)   {   p1=findPrevNode(head,j);   swap1=p1.next;   swap2=swap1.next;   n2=swap2.next;   //System.out.println(p1.data);   //System.out.println(swap1.data);…

class BSTNode  {      int key;      BSTNode left, right;        public BSTNode(int item) {            key = item;            left = right = null;      } }     class BST_Tree  {            BSTNode root;        BST_Tree()  {   // Constructor            root = null;      }       boolean search(int key){         return (searchRec(root, key) != null);     }          public BSTNode searchRec(BSTNode root, int key) {          if (root==null || root.key==key)            return root;              if (root.key > key)            return searchRec(root.left, key);              return searchRec (root.right, key);     }              void deleteKey(int key) {            root = deleteRec(root, key);      }      /* A recursive function to insert a new key in BST */      BSTNode deleteRec(BSTNode root, int key) {            /* Base Case: If the tree is empty */            if (root == null) return root;              /* Otherwise, recur down the tree */            if (key < root.key)…

I need an explanation for this program. class Directory { Node head,tail; Directory() { head=null; tail=null; } public void insert(Node node) // method that insers node into list if phone number is new { Node temp=head; while(temp!=null && !temp.phone_number.equals(node.phone_number)) temp=temp.next; if(temp!=null) { System.out.println("Entered phone number already exists"); return; } if(head==null) { head=node; tail=node; } else { tail.next=node; tail=node; } System.out.println("Inserted Successfully"); } public void remove(String ph_no) // method that removes node with given phone number { Node prev=null; Node node=head; while(node!=null && !node.phone_number.equals(ph_no)) { prev=node;…

import java.util.*; public class Main{    public static void main(String[] args)    {        Main m = new Main();        m.go();    }        private void go()    {        List<Stadium> parks = new ArrayList<Stadium>();                parks.add(new Stadium("PNC Park", "Pittsburgh", 38362, true));        parks.add(new Stadium("Dodgers Stadium", "Los Angeles", 56000, true));        parks.add(new Stadium("Citizens Bank Park", "Philadelphia", 43035, false));        parks.add(new Stadium("Coors Field", "Denver", 50398, true));        parks.add(new Stadium("Yankee Stadium", "New York", 54251, false));        parks.add(new Stadium("AT&T Park", "San Francisco", 41915, true));        parks.add(new Stadium("Citi Field", "New York", 41922, false));        parks.add(new Stadium("Angels Stadium", "Los Angeles", 45050, true));                Collections.sort(parks, Stadium.ByKidZoneCityName.getInstance());        for (Stadium s : parks)            System.out.println(s);    }}…

i need it ASAP please

write this code below as algorithim to determine the leaf node reclusively ?  public static void printLeafNodes(TreeNode node) {        // base case        if (node == null) {            return;        }        if (node.left == null && node.right == null) {            System.out.printf("%d ", node.value);        }        printLeafNodes(node.left);        printLeafNodes(node.right);    }

class BSTNode  {      int key;      BSTNode left, right;        public BSTNode(int item) {            key = item;            left = right = null;      } }     class BST_Tree  {            BSTNode root;        BST_Tree()  {   // Constructor            root = null;      }       boolean search(int key){         return (searchRec(root, key) != null);     }          public BSTNode searchRec(BSTNode root, int key) {          if (root==null || root.key==key)            return root;              if (root.key > key)            return searchRec(root.left, key);              return searchRec (root.right, key);     }              void deleteKey(int key) {            root = deleteRec(root, key);      }      /* A recursive function to insert a new key in BST */      BSTNode deleteRec(BSTNode root, int key) {            /* Base Case: If the tree is empty */            if (root == null) return root;              /* Otherwise, recur down the tree */            if (key < root.key)…

Redesign LaptopList class from previous project public class LaptopList {       private class LaptopNode  //inner class     {         public String brand;         public double price;         public LaptopNode next;           public LaptopNode(String brand, double price)         {                // add your code         }         public String toString()         {             // add your code         }     }       private LaptopNode head; // head of the linked list       public LaptopList(String fname) throws IOException     {         File file = new File(fname);         Scanner scan = new Scanner(file);         head = null;         while(scan.hasNextLine())         {             // scan data             // create LaptopNode             // call addToHead and addToTail alternatively          }     }       private void addToHead(LaptopNode node)     {             // add your code     }       private void addToTail(LaptopNode node)     {             // add your code     }       private…

PLEASE HELP, PYTHON THANK YOU def add_vertex(self, vertex):        if vertex not in self.__graph_dict:            self.__graph_dict[vertex] = []    def add_edge(self, edge):        edge = set(edge)        (vertex1, vertex2) = tuple(edge)        #################        # Problem 4:        # Check to see if vertex1 is in the current graph dictionary        ##################        #DELETE AND PUT IN THE IF STATEMENTS            self.__graph_dict[vertex1].append(vertex2)        else:            self.__graph_dict[vertex1] = [vertex2]    def __generate_edges(self):        edges = []        #################        # Problem 5:        # Loop through all of the data in the graph dictionary and use the variable vertex for the loop'ed data        ##################        #DELETE AND PUT IN THE LOOP STATEMENTS            for neighbour in self.__graph_dict[vertex]:                if {neighbour, vertex} not in edges:                    edges.append({vertex, neighbour})        return edges…