thanhnguyennguyen / cff

    // put your code here to address problems

        // - Pop out all elements from Stack1, push to Stack2

        while (this.stack1.top()) {

            this.stack2.push(this.stack1.pop());

        }

        // - Push new record to Stack1

        this.stack1.push(record);

        // - Pop out all elements from Stack2, push back to Stack1

        while (this.stack2.top()) {

            this.stack1.push(this.stack2.pop());

        }

    }

    dequeue() {

        return this.stack1.pop();

    }

    peek() {

        return this.stack1.data;

    }

}

class Queue2 {

    // put your code here to address problems

    constructor(stack1, stack2) {

        this.stack1 = stack1;

        this.stack2 = stack2;

    }

    enqueue(record) {

        this.stack1.push(record);

    }

    dequeue() {

        let result;

        // - Pop out all elements from Stack1, push to Stack2

        while (this.stack1.top()) {

            this.stack2.push(this.stack1.pop());

        }

        // - Pop from Stack2

        result = this.stack2.pop();

        // - Pop out all remaining elements from Stack2, push back to Stack1

        while (this.stack2.top()) {

            this.stack1.push(this.stack2.pop());

        }

        return result;

    }

    peek() {

        return this.stack1.data;

    }

}

module.exports = {

    Queue1,

    Queue2

};