DSA-in-Java/Queue2S.java at main · shajiyakhan1309/DSA-in-Java · GitHub

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//queue using 2 stacks
import java.util.*;


public class Queue2S {
   static class Queue {
       static Stack<Integer> s1 = new Stack<>();
       static Stack<Integer> s2 = new Stack<>();


       public static boolean isEmpty() {
           return s1.isEmpty();
       }


       public static void add(int data) {
           while(!s1.isEmpty()) {
               s2.push(s1.pop());
           }
           s1.push(data);
           while(!s2.isEmpty()) {
               s1.push(s2.pop());
           }
       }


       public static int remove() {
           return s1.pop();
       }


       public static int peek() {
           return s1.peek();
       }
   }
   public static void main(String args[]) {
       Queue q = new Queue();
       q.add(1);
       q.add(2);
       q.add(3);


       while(!q.isEmpty()) {
           System.out.println(q.peek());
           q.remove();
       }
   }
}