Queue using to stacks

Author: ahmedrafat-SW

src/main/java/com/dev/arrayandhashing/QueueWithTwoStacks.java

@@ -0,0 +1,39 @@
+package com.dev.arrayandhashing;
+
+import java.util.Stack;
+
+public class QueueWithTwoStacks {
+    Stack<Integer> stack1 = new Stack<>();
+    Stack<Integer> stack2 = new Stack<>();
+
+    public void enqueue(int i){
+        this.stack1.push(i);
+    }
+
+    public Integer dequeue(){
+        if (stack1.isEmpty() && stack2.isEmpty()){
+            throw new RuntimeException("No Elements in Queue");
+        }
+        if (stack2.isEmpty()){
+            while (!stack1.isEmpty()){
+                stack2.push(stack1.pop());
+            }
+        }
+
+        return stack2.pop();
+    }
+
+    public static void main(String[] args) {
+
+        QueueWithTwoStacks queue = new QueueWithTwoStacks();
+        queue.enqueue(1);
+        queue.enqueue(2);
+        queue.enqueue(3);
+        System.out.println(queue.dequeue()); // Output: 1
+        System.out.println(queue.dequeue()); // Output: 2
+        queue.enqueue(4);
+        System.out.println(queue.dequeue()); // Output: 3
+        System.out.println(queue.dequeue()); // Output: 4
+
+    }
+}