class MyQueue {public:    /** Initialize your data structure here. */    stack
     
       r, b;    MyQueue() {            }        /** Push element x to the back of queue. */    void push(int x) {        r.push(x);    }        /** Removes the element from in front of queue and returns that element. */    int pop() {        if (b.empty()) {            int size = r.size();            for (int i = 0; i < size; i++) {                int t = r.top();                b.push(t);                r.pop();            }        }        int ret = b.top();        b.pop();        return ret;    }        /** Get the front element. */    int peek() {        if (b.empty()) {            int size = r.size();            for (int i = 0; i < size; i++) {                int t = r.top();                b.push(t);                r.pop();            }        }        return b.top();    }        /** Returns whether the queue is empty. */    bool empty() {        return r.empty() && b.empty();    }};