listAlgorithms/TwoStackQueue.java

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package listAlgorithms;

public class TwoStackQueue<T extends Comparable<T>> {

    private Stack<T> mStore = new Stack<T>();
    private Stack<T> mQueue = new Stack<T>();

    protected void copyToStore() {
        while (mQueue.peek() != null) {
            mStore.push(mQueue.pop());
        }
    }

    protected void copyFromStore() {
        while (mStore.peek() != null) {
            mQueue.push(mStore.pop());
        }
    }

    public void enqueue(T val) {
        copyToStore();
        mQueue.push(val);
        copyFromStore();
    }

    public T peek() {
        T queueVal = mQueue.peek();
        return queueVal;
    }

    public T dequeue() {
        T queueVal = mQueue.pop();
        return queueVal;
    }
}