#include <iostream>
#include <vector>
#include<bits/stdc++.h>

using namespace std;

template<class T>
class ICircularBoundedQueue
{
        public:
        virtual void offer(T value) = 0;
        virtual T poll() = 0;
        virtual T peek() = 0;
        virtual void flush() = 0;
        virtual bool isEmpty() const = 0;
        virtual bool isFull() const = 0;
        virtual int size() const = 0;
        virtual int capacity() const = 0;
        virtual ~ICircularBoundedQueue() = default;
};

template <class T, int Capacity>
class Queue : public ICircularBoundedQueue<T>{

        int a[Capacity];
        int l = 0, r = -1;
public:
         void add(T &x, int val){
                x += val;
                x %= Capacity;
                x += Capacity;
                x %= Capacity;
        }

        virtual void offer(T new_variable)override
        {
                if(r != -1 && (r + 1) % Capacity == l){
                        add(l, 1);
                }
                add(r, 1);
                a[r] = new_variable;
        }

        virtual T poll()override
        {
                if(r == -1){
                        return -1;
                }
                int x = a[l];
                if(l == r){
                        r = -1;
                        l = 0;
                }else add(l, 1);
                return x;
        }

        virtual T peek()override
        {
                if(r == -1)return -1;
                return a[l];
        }

        virtual void flush()override
        {
                l = 0, r = -1;
        }

        virtual bool isFull() const override
        {
                return (r + 1) % Capacity == l;
        }

        virtual bool isEmpty() const override
        {
                return (r == -1);
        }

        virtual int size() const override
        {
                if(r == -1)return 0;
                if(l <= r)return r - l + 1;
                return Capacity - l + r + 1;
        }

        virtual int capacity() const override
        {
                return Capacity;
        }

};