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JavaDS.java

@@ -26,36 +26,36 @@ public static void main(String[] args){
         QUEUE1.display();
 
 
-        //linkedlist teseter
-        LinkedList list = new LinkedList();
-        list.addToTail(5);
-        list.addToTail(2);
-        list.addToTail(-2);
-        System.out.println(list.removeHead()+ " Is the head, and it's been removed");
-        System.out.println(list.getHead()+" This is the new head");
-        list.addToTail(3);
-        list.addToTail(1000);
-        System.out.println(list.contains(1000));
-
-        //tree tester
-        Tree tree = new Tree();
-        int[] items = {5, 8, 7, 1, 9, 3, 0, 4, 6, 2};
-        for (int i : items)
-            tree.addChild(i);
-
-        System.out.println("Is it contain 3: " + tree.contains(3));
-        tree.display();
-
-
-        //hashtable tester
-        HashTable hashTable = new HashTable();
-        // Put some key values.
-        hashTable.insert("cat","1");
-        hashTable.insert("cat","2");
-        hashTable.insert("dog","3");
-        hashTable.remove("cat");
-        System.out.println(hashTable.retrieve("dog"));
-    }
-
-}
+//         //linkedlist teseter
+//         LinkedList list = new LinkedList();
+//         list.addToTail(5);
+//         list.addToTail(2);
+//         list.addToTail(-2);
+//         System.out.println(list.removeHead()+ " Is the head, and it's been removed");
+//         System.out.println(list.getHead()+" This is the new head");
+//         list.addToTail(3);
+//         list.addToTail(1000);
+//         System.out.println(list.contains(1000));
+
+//         //tree tester
+//         Tree tree = new Tree();
+//         int[] items = {5, 8, 7, 1, 9, 3, 0, 4, 6, 2};
+//         for (int i : items)
+//             tree.addChild(i);
+
+//         System.out.println("Is it contain 3: " + tree.contains(3));
+//         tree.display();
+
+
+//         //hashtable tester
+//         HashTable hashTable = new HashTable();
+//         // Put some key values.
+//         hashTable.insert("cat","1");
+//         hashTable.insert("cat","2");
+//         hashTable.insert("dog","3");
+//         hashTable.remove("cat");
+//         System.out.println(hashTable.retrieve("dog"));
+//     }
+
+// }
 

LinkedList.java

@@ -1,28 +1,70 @@
-public class LinkedList {
-    public Node head;
 
-    public void addToTail(int data) {
+       public class LinkedList {
+
+       public Node head=new Node();
+       public Node tail=new Node();
+
+
+
+
+       public void addToTail(int data) {
         //your code is here
+         Node node1=new Node();
+
+         node1.value=data;
+
+        if(head.next==null){
+         head.next=node1;
+        }
+        if(tail.next!=null){
+            tail.next.next=node1;
+
+        }
+        tail.next=node1;
+
     }
 
     public boolean contains(int value) {
         //your code is here
+        Node node1 =head;
+        while(node1.next!=null){
+            if(node1.value==value){
+                return true;
+            }
+            node1=node1.next;
+        }
+        if(node1.value==value){
+            return true;
+        }
+        return false;
     }
 
     public int removeHead() {
         //your code is here
-    }
+        if(head.next!=null){
+
+            if(head.next.next==null){
+                tail.next=null;
+            }
+
+            Node node1=head.next;
+            head.next=node1.next;
+            return node1.value;
+        }
+        else {
+            return 0;}
 
-    public void printList() {
-        //your code is here
     }
 
-    public int getHead() {
+    public void printList() {
         //your code is here
     }
+
 
     public class Node {
         //your code is here
+        public int value ;
+        public Node next;
     }
 
 }

Queue.java

@@ -1,13 +1,43 @@
-public class Queue {
-   // your code is here
-    public void push(int pushedElement){
-       //your code is here
-    }
+import java.util.Arrays;
+
+
+public class Queue{
+
+int [] arr=new int [3];
+  int front=0;
+  int rear=0;
+  int numberelem=0;
+
+
+     public void push(int elem){
+     if(numberelem<3){
+      arr[rear]=elem;
+      rear++;
+      numberelem++;
+
+        }
+        else {
+          System.out.println("overflow");
+        }
+      }
+
+
     public void pop(){
-        //your code is here
+         if(numberelem>0){
+          arr[front]="-1";
+          front++;
+          numberelem--;
+         }
+         else{
+          System.out.println("queue is empty");
+         }
+
+
     }
+
     public void display(){
-        //your code is here
+      for(int i=0;i<3;i++){
+        System.out.println(arr[i]);
+      }
     }
-
 }

Stack.java

@@ -1,10 +1,33 @@
-public class Stack {
-    //your code is here
-    public void push(int pushedElement){
-       //your code is here
-    }
-    public void pop() {
-        //your code is here
+ import java.util.Arrays;
+
+public class Stack{
+ public int []= new int[3];
+ public numberelem=0;
+ public top=-1;
+
+ public void push(int elem){
+    if(numberelem<3){
+     arr[top+1]=elem;
+     top++;
+        } 
+     }
+     else{
+         System.out.println("stack is full "); 
+     }
+
+
+   public void pop(){
+    if(numberelem>0){
+        top--;
+      }
+    else{
+        System.out.println("stack is empty "); 
     }
+   }
+
+
+
+}
+
+
 
-}