Update Stack using 2 Queues

Author: akshayavb99

Course 2 - Data Structures in JAVA/Lecture 10 - Queues/Stack using 2 Queues

@@ -65,3 +65,79 @@ true
 -1
 false
 */
+import java.util.*;
+public class Stack {
+
+    //Define the data members
+    private Queue<Integer> q1;
+    private Queue<Integer> q2;
+    private int size;
+
+
+    public Stack() {
+        //Implement the Constructor
+        q1=new LinkedList<Integer>();
+        q2=new LinkedList<Integer>();
+        size=0;
+    }
+
+
+
+    /*----------------- Public Functions of Stack -----------------*/
+
+
+    public int getSize() { 
+        //Implement the getSize() function
+        return size;
+    }
+
+    public boolean isEmpty() {
+        //Implement the isEmpty() function
+        return size==0;
+    }
+
+    public void push(int element) {
+        //Implement the push(element) function
+        q1.add(element);     
+        size=size+1;
+    }
+
+    public int pop() {
+        //Implement the pop() function
+       if (q1.isEmpty())
+       {
+           return -1;
+       }
+       while(q1.size()!=1)
+       {
+           q2.add(q1.remove());
+       }
+       int top=q1.remove();
+        
+       while(!q2.isEmpty())
+       {
+           q1.add(q2.remove());
+       }
+       size=size-1;
+        return top;
+    }
+
+    public int top() {
+        //Implement the top() function
+        if (q1.isEmpty())
+       {
+           return -1;
+       }
+       while(q1.size()!=1)
+       {
+           q2.add(q1.remove());
+       }
+       int top=q1.peek();
+       q2.add(q1.remove());
+       
+       Queue<Integer> q=q1;
+       q1=q2;
+       q2=q;
+       return top;
+    }
+}